Sample records for intergalactic space

  1. ISO proves that intergalactic space is dusty

    NASA Astrophysics Data System (ADS)

    1997-11-01

    In the past, astronomers have considered intergalactic space to be extremely clean. Except in the vast concentrations of stars, gas and dust that make up the galaxies themselves, the Universe was supposed to be filled only by very thin traces of invisible gas. ISO's detection of dust means that the Universe is less transparent than astronomers have assumed. Their cosmic window-pane is slightly dirty and large-scale inferences based on the brightnesses of distant galaxies and quasars may be affected. Emissions from the intergalactic dust were picked up by the photometer ISOPHOT. A team of German, British, Spanish and Danish astronomers contributed this versatile set of detectors to ISO. The leader of the ISOPHOT team is Dietrich Lemke of the Max-Planck Institut fr Astronomie (MPIA) in Heidelberg, Germany. "ISOPHOT in ISO is the only instrument in existence capable of making this detection" Lemke says. "The intergalactic dust is so cold that we need a very cold telescope to detect it. The strongest emissions from the dust are at a wavelength of 0.1-0.2 millimetre, which cannot be well observed from the Earth. ISO provides telescope in space cooled by superfluid helium to within 2 degrees of absolute zero. ISOPHOT is the instrument on ISO that measures infrared intensities at the longest wavelengths, up to 0.2 millimetre." ISOPHOT's advantages made finding the intergalactic dust possible, but not easy. The observations pushed instrumental sensitivity to the limit, and emissions from cold dust clouds in the Milky Way Galaxy confused the picture. The signal of intergalactic dust emerged clearly only after extensive data analysis. Cold dust in a hot cluster Our home Galaxy, the Milky Way, belongs to a very small group of galaxies. Intergalactic dust may very well be present nearby, but it is likely to be sparse and scattered. A team of astronomers, from MPIA Heidelberg and Helsinki Observatory, hoped that the intergalactic dust might be easier to recognise in a large cluster of galaxies. They chose the Coma Cluster, which fills an area of the sky twice as wide as the Full Moon even though it is about 450 million light-years away. ISO scanned the Coma Cluster twice, along different cross-sections, measuring with ISOPHOT its emissions of long-wavelength infrared rays. The hunch of the German-Finnish team turned out to be correct. Emissions indicating the presence of intergalactic dust were much stronger towards the crowded centre of the cluster than at the edges. The results on the Coma Cluster obtained with ISO seem to contradict, at first sight, observations of the same cluster by another space observatory built in Europe. The German-US-UK Rosat satellite for X-ray astronomy has charted X-rays coming from very hot gas between the galaxies, and concentrated towards the centre of the Coma Cluster. The intergalactic gas detected by Rosat has a temperature of 80 million degrees, far hotter even than the core of the Sun. "The dust particles are at the very cold end of the temperature scale," says Kalevi Mattila of Helsinki Observatory. "ISOPHOT allows us to measure temperatures for them, in the range minus 220 to minus 250 degrees Celsius." How can cold dust at minus 250 degrees survive within a very hot gas? The gas is extremely tenuous, so it cannot simply warm the grains of dust like a hair-drier. Instead the hot gas subjects the dust to impacts by energetic atomic particles which knock atoms out of it, and so gradually erode the dust grains. Calculations suggest that the hot gas will destroy the cold dust in about 100 million years. Although that is very slow by human standards, it represents only one-hundredth of the age of the galaxies. Experts therefore have to consider where fresh supplies of intergalactic dust come from. Rosat astronomers found that the Coma Cluster is not spherical, which would be the shape expected in an isolated cluster. By X-rays, the cloud of hot intergalactic gas is seen to be egg-shaped. The same shape is apparent in the intergalactic dust cloud observed by IS

  2. Transonic galactic outflows and their influences to the chemical evolution of galaxies and intergalactic space

    NASA Astrophysics Data System (ADS)

    Igarashi, Asuka; Mori, Masao; Nitta, Shin-ya

    2014-05-01

    Galactic winds are widely recognized as important ingredients in galaxy evolution, and they impact the chemical enrichment of galaxies and the intergalactic medium. We investigate the acceleration process of isothermal, spherically symmetric steady galactic outflows in an appropriate galactic gravitational potential applying the transonic analysis which is the well-known approach for the solar wind. The results show that the transonic solutions of the galactic winds critically depend upon the mass distribution in a galaxy such as the dark matter halo (DMH) and the central super massive black hole (SMBH). We discover the existence of two types of transonic solutions in the gravity from the combination of DMH and SMBH. The first one is accelerated near the SMBH which is similar to the Parker solution, and the other is slowly accelerated over the entire region of DMH. These two transonic solutions have different mass fluxes and starting points. Therefore, they have different influences to the chemical evolution of galaxies and intergalactic space. We have found that the mass fluxes of two transonic solutions are considerably different by several orders of magnitude in spite of the same mass distribution. This result indicates that mass flux is very sensitive not only to the mass distribution but also to the chosen transonic solution.

  3. Testing a novel method to map the 3D distribution of gas clouds in intergalactic space

    E-print Network

    Bardalez Gagliuffi, Daniella C

    2011-01-01

    We propose a new method to detect intergalactic Lyman a emitter and absorber systems by comparing broadband and narrowband images. The narrowband observations were carried out with the Maryland-Magellan Tunable Filter ...

  4. Intergalactic Travel Bureau

    NASA Astrophysics Data System (ADS)

    Koski, Olivia; Rosin, Mark; Guerilla Science Team

    2014-03-01

    The Intergalactic Travel Bureau is an interactive theater outreach experience that engages the public in the incredible possibilities of space tourism. The Bureau is staffed by professional actors, who play the role of space travel agents, and professional astrophysicists, who play the role of resident scientists. Members of the public of all ages were invited to visit with bureau staff to plan the vacation of their dreams-to space. We describe the project's successful nine day run in New York in August 2013. Funded by the American Physical Society Public Outreach and Informing the Public Grants.

  5. Scatter broadening of compact radio sources by the ionized intergalactic medium: prospects for detection with Space VLBI and the Square Kilometre Array

    NASA Astrophysics Data System (ADS)

    Koay, J. Y.; Macquart, J.-P.

    2015-01-01

    We investigate the feasibility of detecting and probing various components of the ionized intergalactic medium (IGM) and their turbulent properties at radio frequencies through observations of scatter broadening of compact sources. There is a strong case for conducting targeted observations to resolve scatter broadening (where the angular size scales as ˜?-2) of compact background sources intersected by foreground galaxy haloes and rich clusters of galaxies to probe the turbulence of the ionized gas in these objects, particularly using Space very long baseline interferometry (VLBI) with baselines of 350 000 km at frequencies below 800 MHz. The sensitivity of the Square Kilometre Array (SKA) allows multifrequency surveys of interstellar scintillation (ISS) of ˜ 100 ?Jy sources to detect or place very strong constraints on IGM scatter broadening down to ˜ 1 ?as scales at 5 GHz. Scatter broadening in the warm-hot component of the IGM with typical overdensities of ˜30 cannot be detected, even with Space VLBI or ISS, and even if the outer scales of turbulence have an unlikely low value of ˜1 kpc. None the less, intergalactic scatter broadening can be of the order of ˜ 100 ?as at 1 GHz and ˜ 3 ?as at 5 GHz for outer scales ˜1 kpc, assuming a sufficiently high-source redshift that most sight-lines intersect within a virial radius of at least one galaxy halo (z ? 0.5 and 1.4 for 1010 and 1011 M? systems, following McQuinn 2014). Both Space VLBI and multiwavelength ISS observations with the SKA can easily test such a scenario, or place strong constraints on the outer scale of the turbulence in such regions.

  6. An Intergalactic Voyage.

    ERIC Educational Resources Information Center

    Wethered, Peggy Ann

    1997-01-01

    Describes an event called Star Week that involved families joining in their children's projects, attending an educational presentation by the National Aeronautics and Space Administration (NASA), and participating in a schoolwide star party. Contains resources for both students and teachers. (JRH)

  7. On the Origin of Intergalactic Gas in Clusters of Galaxies and Sources of its Energy

    NASA Astrophysics Data System (ADS)

    Gorbatsky, V. G.

    1988-07-01

    The data on Fe abundances in intergalactic gas (IGG) and on mass of IGG are briefly discussed. The evolution of this abundances is considered and results of calculations are compared with the observational data on clusters of galaxies. It is found that the prevailing part of IGG consists of interstellar gas sweeped with the galactic wind from galaxies to the intergalactic space. Some consequences of this fact are mentioned, in particular, related to the problem of heating of IGG.

  8. Intergalactic shells at large redshift

    NASA Technical Reports Server (NTRS)

    Shull, J. M.; Silk, J.

    1981-01-01

    The intergalactic shells produced by galactic explosions at large redshift, whose interiors cool by inverse Compton scattering off the cosmic background radiation, have a characteristic angular size of about 1 arcmin at peak brightness. At z values lower than 2, the shells typically have a radius of 0.5 Mpc, a velocity of about 50 km/sec, a metal abundance of about 0.0001 of cosmic values, and strong radiation in H I(Lyman-alpha), He II 304 A, and the IR fine-structure lines of C II and Si II. The predicted extragalactic background emission from many shells, strongly peaked toward the UV, sets an upper limit to the number of exploding sources at z values of about 10. Shell absorption lines of H I, C II, Si II, and Fe II, which may be seen at more recent epochs in quasar spectra, may probe otherwise invisible explosions in the early universe.

  9. arXiv:astroph/0407236 Planetary Nebulae as Tracers of the Intergalactic

    E-print Network

    Buzzoni, Alberto

    limit at #24; 7% for the global B luminosity of the cluster provided by \\loose" intergalactic stars. 1), makes them ideal candidates to trace the \\loose" stellar population possibly #12;lling the \\empty" space by the observations. Population synthesis models can be especially useful in this sense, allowing us to tackle

  10. Physics of the Interstellar and Intergalactic Medium

    E-print Network

    Draine, Bruce T.

    be the ratio of the visual (V band, = 0.55 µm) extinction cross section to the geometric cross section a2Physics of the Interstellar and Intergalactic Medium: Problems for Students Version 2013.02.18 c;#12;Preface I have assembled this collection of problems to accompany Physics of the Interstellar and Inter

  11. X-raying the Intergalactic OVI Absorbers

    E-print Network

    Y. Yao; T. M. Tripp; Q. D. Wang; C. W. Danforth; C. R. Canizares; J. M. Shull; H. L. Marshall; L. Song

    2009-03-23

    The observed intergalactic OVI absorbers at z>0 have been regarded as a significant reservoir of the ``missing baryons''. However, to fully understand how these absorbers contribute to the baryon inventory, it is crucial to determine whether the systems are collisionally ionized or photoionized (or both). Using the identified intergalactic OVI absorbers as tracers, we search for the corresponding X-ray absorption lines, which are useful for finding the missing baryons and for revealing the nature of the OVI absorbers. Stacking the Chandra grating spectra along six AGN sight lines, we obtain three spectra with signal-to-noise ratios of 32, 28, and 10 per 12.5 mA spectral bin around the expected OVII Kalpha wavelength. These spectra correspond to OVI absorbers with various dynamic properties. We find no detectable NeIX, OVII, OVIII, NVII, or CVI absorption lines in the spectra, but the high counting statistics allows us to obtain firm upper limits on the corresponding ionic column densities (in particular N(OVII)<=10 N(OVI) on average at the 95% confidence level). Jointly analyzing these non-detected X-ray lines with the averaged OVI column density, we further limit the average temperature of the OVI-bearing gas to be log[T(K)]<=5.7 in collisional ionization equilibrium. We discuss the implications of these results for physical properties of the putative warm-hot intergalactic medium and its detection in future X-ray observations.

  12. Galactic Corona or Local Group Intergalactic Medium?

    E-print Network

    Rik J. Williams; Smita Mathur; Fabrizio Nicastro

    2005-11-21

    Cosmological hydrodynamic simulations predict that the low redshift universe comprises a web of warm-hot intergalactic gas and galaxies, with groups of galaxies and clusters forming at dense knots in these filaments. Our own Galaxy being no exception is also expected to be surrounded by the warm-hot intergalactic medium, filling the Local Group. Some theoretical models also predict the existence of a hot Galactic corona. With X-ray and FUV observations of extragalactic sources, we can probe the warm-hot gas through absorption lines of highly ionized elements. Indeed, Chandra, XMM and FUSE observations have detected z=0 absorption lines toward many sightlines. The debate that has emerged is over the interpretation of these observations: are the z=0 absorption systems from the halo of our Galaxy or from the extended Local Group environment? This has important implications for our understanding of the mass of the Local Group, the physical conditions in the intergalactic medium, the structure of the Galaxy and galaxy formation in general. We will present the current status of the debate and discuss our ongoing observing program aimed at understanding the z=0 absorption systems, with an emphasis on the high quality Chandra spectra of the Mrk 421 and Mrk 279 sightlines.

  13. X-ray Studies of Interstellar and Intergalactic Dust

    NASA Astrophysics Data System (ADS)

    Corrales, Lia; Paerels, F. B.

    2014-01-01

    Dust grain composition, sizes, and spatial distribution can be directly measured with high resolution X-ray imaging and spectroscopy. Dust in the foreground of bright point sources will scatter X-rays through small angles, producing a diffuse `halo' image. The scattering cross-section is most sensitive to large dust grains, which are typically missed in UV, optical, and infrared studies. The dust-to-gas mass ratio and elemental constituents of dust grains can also be determined from X-ray spectroscopy. I demonstrate how a Bayesian analysis of the scattering halo around Cyg X-3 yields a grain size distribution and mass ratio that does not match properties typically assumed of Galactic dust. Finally, I will discuss the prospects for using quasars to measure the cosmic density of dust grains in intergalactic space.

  14. Ensemble fluctuations of the cosmic ray energy spectrum and the intergalactic magnetic field

    NASA Astrophysics Data System (ADS)

    Supanitsky, A. D.; Medina-Tanco, G.

    2015-06-01

    The origin of the most energetic cosmic ray particles is one of the most important open problems in astrophysics. Despite a big experimental effort done in the past years, the sources of these very energetic particles remain unidentified. Therefore, their distribution on the Universe and even their space density are still unknown. It has been shown that different spatial configurations of the sources lead to different energy spectra and composition profiles (in the case of sources injecting heavy nuclei) at Earth. These ensemble fluctuations are more important at the highest energies, because only nearby sources, which are necessarily few, can contribute to the flux observed at Earth. This is due to the interaction of the cosmic rays with the low energy photons of the radiation field, present in the intergalactic medium, during propagation. It is believed that the intergalactic medium is permeated by a turbulent magnetic field. Although at present it is still unknown, there are several constraints for its intensity and coherence length obtained from different observational techniques. Charged cosmic rays are affected by the intergalactic magnetic field because of the bending of their trajectories during propagation through the intergalactic medium. In this work, the influence of the intergalactic magnetic field on the ensemble fluctuations is studied. Sources injecting only protons and only iron nuclei are considered. The ensemble fluctuations are studied for different values of the density of sources compatible with the constraints recently obtained from cosmic ray data. Also, the possible detection of the ensemble fluctuations in the context of the future JEM-EUSO mission is discussed.

  15. Thermal Evolution of the Intergalactic Medium

    NASA Astrophysics Data System (ADS)

    Upton Sanderbeck, Phoebe; McQuinn, Matthew

    2015-01-01

    The thermal evolution of the intergalactic medium (IGM) can provide clues regarding the reionization history of the IGM. Recent temperature measurements of the IGM from Lyman alpha forest data have given insight into the timeline of these reionization events, specifically the reionization of HeII at z~3. We model the thermal history of the IGM from HI reionization through HeII reionization based on well established heating and cooling processes. We present a comparison of such modeling of the thermal evolution with the recent observational constraints anddiscuss additional heating mechanisms.

  16. Intergalactic Magnetic Fields from Quasar Outflows

    E-print Network

    Steven Furlanetto; Abraham Loeb

    2001-02-05

    Outflows from quasars inevitably pollute the intergalactic medium (IGM) with magnetic fields. The short-lived activity of a quasar leaves behind an expanding magnetized bubble in the IGM. We model the expansion of the remnant quasar bubbles and calculate their distribution as a function of size and magnetic field strength at different redshifts. We generically find that by a redshift z=3, about 5-20% of the IGM volume is filled by magnetic fields with an energy density >10% of the mean thermal energy density of a photo-ionized IGM (at T=10^4 K). As massive galaxies and X-ray clusters condense out of the magnetized IGM, the adiabatic compression of the magnetic field could result in the field strength observed in these systems without a need for further dynamo amplification. The intergalactic magnetic field could also provide a nonthermal contribution to the pressure of the photo-ionized gas that may account for the claimed discrepancy between the simulated and observed Doppler width distributions of the Ly-alpha forest.

  17. Did Cosmic Rays Reionize the Intergalactic Medium?

    E-print Network

    Biman B. Nath; Peter L. Biermann

    1993-06-02

    We investigate the role of cosmic rays from young galaxies in heating and ionizing the intergalactic medium (IGM) at high redshift. Using the IRAS observations at $60 \\mu m$, we estimate the cosmic ray luminosity density at the present epoch. We consider various forms of luminosity evolution in redshift and calculate (a) the thresholds corresponding to the upper limits of Gunn-Peterson optical depth, (b) the Compton $y$ parameter for an IGM heated by cosmic rays and compare with the upper limits from COBE measurements and (c) an estimated limit from the integral of metal enrichment. We show that certain models, with rather strong evolution and early formation of galaxies, allow reionization of the IGM, consistent with all known constraints.

  18. Intergalactic Matter and Cocoons of Radio Galaxies

    E-print Network

    Biman B. Nath

    1994-12-03

    The cocoons surrounding powerful radio sources can be extensive if the jet that feeds the cocoon is light and supersonic. They have been shown to remain overpressured with respect to the ambient medium for most of the life time of the sources. The observed lobes of the radio sources form parts of these extensive cocoons. We show that observations of the lobes of giant radio sources allow one to estimate the {\\it density} of the intergalactic medium (IGM) in which the lobes are embedded. We estimate the IGM density to be of the order of a few percent of the closure density of the universe. We further calculate the radio power of the overpressured cocoon as a function of time and the ambient density.

  19. Cosmological halos as a new test for intergalactic gas

    NASA Astrophysics Data System (ADS)

    Sholomitskij, G. B.; Yaskovitch, A. L.

    1990-10-01

    A test for the electron density of a general intergalactic gas is proposed, based on observations of the local Thomson scattering of radiation (light echos or cosmological halos) around quasars with high redshifts. The estimates made show that observations of cosmic halos around radio-loud quasars by polarized flux density synthesis with tangential polarization make it possible to measure the mean density parameter of the intergalactic gas with an instrumental accuracy of approximately 0.01.

  20. Enrichment of the Intergalactic Medium by the Milky Way Subgroup

    E-print Network

    Leticia Carigi

    2001-08-27

    I study the effect of the galaxies of the Milky Way subgroup on the chemical enrichment of the diffuse gas within the Local Group. The preferred model predicts that the present-day intergalactic medium mass is 1/22 of the initial baryonic mass and its metallicity is 1/20 $Z_\\odot$. Nearly 80 % of intergalactic metals were produced in the Galactic bulge.

  1. Resistive Generation of Intergalactic Magnetic Field at Cosmic Dawn

    NASA Astrophysics Data System (ADS)

    Miniati, F.; Bell, A. R.

    2012-07-01

    Miniati & Bell (2011) proposed a mechanism for the generation of magnetic seeds that is based the finite resistivity of the low temperature IGM in the high redshift universe. In this model, cosmic-ray protons generated by the first generation of galaxies, escape into the intergalactic medium carrying an electric current that induces return currents, jt, and associated electric fields, E = ?jt there. Because the resistivity, ?, depends on the IGM temperature, which is highly inhomogeneous due to adiabatic contraction and shocks produced by structure formation, a non-vanishing curl of the electric field exists which sustains the growth of magnetic field. In this contribution we have developed an approximate numerical model for this process by implementing the source terms of the resistive mechanism in the cosmological code CHARM. Our numerical estimates substantiate the earlier analysis in Miniati & Bell (2011) which found magnetic seeds between 10-18 and 10-16 Gauss throughout cosmic space at redshift z ˜ 6, consistent with conservative estimates of magnetic fields in voids at z ˜ 0 from recent gamma-ray experiments.

  2. Intergalactic stellar populations in intermediate redshift clusters

    NASA Astrophysics Data System (ADS)

    Melnick, J.; Giraud, E.; Toledo, I.; Selman, F.; Quintana, H.

    2012-11-01

    A substantial fraction of the total stellar mass in rich clusters of galaxies resides in a diffuse intergalactic component usually referred to as the intracluster light (ICL). Theoretical models indicate that these intergalactic stars originate mostly from the tidal interaction of the cluster galaxies during the assembly history of the cluster, and that a significant fraction of these stars could have formed in situ from the late infall of cold metal-poor gas clouds on to the cluster. However, these models also overpredict the fraction of stellar mass in the ICL by a substantial margin, something that is still not well understood. The models also make predictions about the age distribution of the ICL stars, which may provide additional observational constraints. Here we present population synthesis models for the ICL of an intermediate redshift (z = 0.29) X-ray cluster that we have extensively studied in previous papers. The advantage of observing intermediate redshift clusters rather than nearby ones is that the former fit the field of view of multi-object spectrographs in 8-m telescopes and therefore permit us to encompass most of the ICL with only a few well-placed slits. In this paper we show that by stacking spectra at different locations within the ICL it is possible to reach sufficiently high signal-to-noise ratios to fit population synthesis models and derive meaningful results. The models provide ages and metallicities for the dominant populations at several different locations within the ICL and the brightest cluster galaxies (BCG) halo, as well as measures of the kinematics of the stars as a function of distance from the BCG. We thus find that the ICL in our cluster is dominated by old metal-rich stars, at odds with what has been found in nearby clusters where the stars that dominate the ICL are old and metal poor. While we see weak evidence of a young, metal-poor component, if real, these young stars would amount to less than 1 per cent of the total ICL mass, much less than the up to 30 per cent predicted by the models. We propose that the very metal-rich (i.e. 2.5× solar) stars in the ICL of our cluster, which comprise ˜40 per cent of the total mass, originate mostly from the central dumb-bell galaxy, while the remaining solar and metal-poor stars come from spiral, post-starburst (E+A) and metal-poor dwarf galaxies. About 16 per cent of the ICL stars are old and metal poor.

  3. Particle energy cascade in the intergalactic medium

    NASA Astrophysics Data System (ADS)

    Valdés, M.; Evoli, C.; Ferrara, A.

    2010-05-01

    We study the development of high-energy (Ein <= 1 TeV) cascades produced by a primary electron of energy Ein injected into the intergalactic medium (IGM). To this aim we have developed the new code MEDEA (Monte Carlo Energy Deposition Analysis) which includes Bremsstrahlung and inverse Compton (IC) processes, along with H/He collisional ionizations and excitations, and electron-electron collisions. The cascade energy partition into heating, excitations and ionizations depends primarily not only on the IGM ionized fraction, xe, but also on redshift, z, due to IC on cosmic microwave background (CMB) photons. While Bremsstrahlung is unimportant under most conditions, IC becomes largely dominant at energies Ein >= 1 MeV. The main effect of IC at injection energies Ein <= 100 MeV is a significant boost of the fraction of energy converted into low-energy photons (h? < 10.2 eV) which do not further interact with the IGM. For energies Ein >= 1 GeV CMB photons are preferentially upscattered within the X-ray spectrum (h? > 104 eV) and can free stream to the observer. Complete tables of the fractional energy depositions as a function of redshift, Ein and ionized fraction are given. Our results can be used in many astrophysical contexts, with an obvious application related to the study of decaying/annihilating dark matter (DM) candidates in the high-z Universe.

  4. On the intergalactic temperature-density relation

    E-print Network

    McQuinn, Matthew

    2015-01-01

    Cosmological simulations of the low-density intergalactic medium exhibit a strikingly tight power-law relation between temperature and density that holds over two decades in density. It is found that this relation should roughly apply Delta z ~ 1-2 after a reionization event, and this limiting behavior has motivated the power-law parameterizations used in most analyses of the Ly-alpha forest. This relation has been explained by using equations linearized in the baryonic overdensity (which does not address why a tight power-law relation holds over two decades in density) or by equating the photoheating rate with the cooling rate from cosmological expansion (which we show is incorrect). Previous explanations also did not address why recombination cooling and Compton cooling off of the cosmic microwave background, which are never negligible, do not alter the character of this relation. We provide an understanding for why a tight power-law relation arises for unshocked gas at all densities for which collisional c...

  5. THEIA: Telescope for Habitable Exoplanets and Interstellar/Intergalactic Astronomy

    NASA Astrophysics Data System (ADS)

    Spergel, David N.; THEIA Collaboration

    2010-01-01

    Over the past 25 years, the Hubble Space Telescope has revolutionized our view of the universe, excited and engaged the general public with its compelling images, and has been a workhorse for astrophysics. We propose that NASA build THEIA, Telescope for Habitable Exoplanets and Interstellar/Intergalactic Astronomy, a flagship 4-meter on-axis optical/UV telescope as a worthy successor to HST and companion to the James Webb Space Telescope (JWST). With a wide field imager, an ultraviolet spectrograph, a planet imager/spectrograph and a companion occulter, THEIA is capable of addressing many of the most important questions in astronomy: Are we alone? Are there other habitable planets? How frequently do solar systems form and survive? How do stars and galaxies form and evolve? How is dark matter distributed in galaxies and in the filaments? Where are most of the atoms in the universe? How were the heavy elements necessary for life created and distributed through cosmic time? This poster describes the THEIA Observatory, an on-axis three-mirror anastigmat telescope with a 4-meter Al/MgF2-coated primary, an Al/LiF-coated secondary and three main instruments: Star Formation Camera (SFC), a dual-channel wide field UV/optical imager covering 19’ x 15’ on the sky with 18 mas pixels; UltraViolet Spectrograph (UVS) , a a multipurpose spectrometer optimized for high sensitivity observations of faint astronomical sources at spectral resolutions of 30,000 to 100,000 in the 100-300 nm wavelength range; and eXtrasolar Planet Characterizer (XPC), which consists of three narrow-field cameras (250-400 nm; 400-700 nm; 700-1000 nm) and two R/70 integral field spectrographs (IFS).

  6. Intergalactic dust and its photoelectric heating

    NASA Astrophysics Data System (ADS)

    Inoue, A. K.; Kamaya, H.

    2010-01-01

    We have examined dust photoelectric heating in the intergalactic medium (IGM). The heating rate in a typical radiation field of the IGM is represented by ?pe = 1.2×10-34 erg s-1 cm-3 (D/10-4)(nH/10-5 cm-3)4/3 (JL/10-21 erg s-1 cm-2 Hz-1 sr-1)2/3 (T/10-4 K)-1/6, where D is the dust-to-gas mass ratio, nH is the hydrogen number density, JL is the mean intensity at the hydrogen Lyman limit of the background radiation, and T is the gas temperature, if we assume the new X-ray photoelectric yield model by Weingartner et al. (2006) and the dust size distribution in the Milky Way by Mathis et al. (1977). This heating rate dominates the HI and HeII photoionization heating rates when the hydrogen number density is less than ˜10-6 cm-3 if D = 10-4 which is 1% of that in the Milky Way, although the heating rate is a factor of 2-4 smaller than that with the old yield model by Weingartner and Draine (2001). The grain size distribution is very important. If only large (?0.1 ?m) grains exist in the IGM, the heating rate is reduced by a factor of ?5. Since dust heating is more efficient in a lower density medium relative to the photoionization heating, it may cause an inverted temperature-density relation in the low-density IGM, as suggested by Bolton et al. (2008). Finally, we have found that dust heating is not very important in the mean IGM before the cosmic reionization.

  7. The Hot Intergalactic Medium-Galaxy Connection: Two Strong O VI Absorbers in the Sight Line toward PG 1211+143

    Microsoft Academic Search

    Jason Tumlinson; J. Michael Shull; Mark L. Giroux; John T. Stocke

    2005-01-01

    We present Hubble Space Telescope (HST) Space Telescope Imaging Spectrograph (STIS) and Far Ultraviolet Spectroscopic Explorer (FUSE) spectra of the QSO PG 1211+143 (zem=0.081) and a galaxy survey of the surrounding field. This sight line shows two strong intergalactic absorption systems at cz~=15,300 and 19,300 km s-1. This sight line addresses the nature and origin of the O VI absorbers

  8. Intergalactic Helium Absorption toward High-Redshift Quasars

    NASA Technical Reports Server (NTRS)

    Giroux, Mark L.; Fardal, Mark A.; Shull, J. Michael

    1995-01-01

    The recent Hubble Space Telescope (HST) observations of the z(q) = 3.286 quasar Q0302-003 (Jakobsen et at. 1994) and the z(q) = 3.185 quasar Q1935-67 by Tytler (1995) show absorption edges at the redshifted wavelength of He II 304 A. A key goal is to distinguish between contributions from discrete Ly-alpha forest clouds and a smoothly distributed intergalactic medium (IGM). We model the contributions from each of these sources of He II absorption, including the distribution of line Doppler widths and column densities, the 'He II proximity effect' from the quasar, and a self-consistent derivation of the He II opacity of the universe as a function of the spectrum of ionizing sources, with the assumption that both the clouds and the IGM are photoionized. The He II edge can be fully accounted for by He II line blanketing for reasonable distributions of line widths and column densities in the Ly-alpha forest, provided that the ionizing sources have spectral index alpha(s) greater than 1.5, and any He II proximity effect is neglected. Even with some contribution from a diffuse IGM, it is difficult to account for the edge observed by Jakobsen et al. (1994) with a 'hard' source spectrum (alpha(s) less than 1.3). The proximity effect modifies the relative contributions of the clouds and IGM to tau(He II) near the quasar (z approx. less than z(q)) and markedly increases the amount of He II absorption required. This implies, for example, that to account for the He II edge with line blanketing alone, the minimum spectral index alpha(s) must be increased from 1.5 to 1.9. We demonstrate the need for higher resolution observations that characterize the change in transmission as z approaches z(q) and resolve line-free gaps in the continuum. We set limits on the density of the diffuse IGM and suggest that the IGM and Ly-alpha clouds are likely to be a significant repository for dark baryons.

  9. Galactic structure and turbulence, pulsar distances, and the intergalactic medium

    NASA Astrophysics Data System (ADS)

    Cordes, J. M.

    2013-03-01

    This paper summarizes how multi-wavelength measurements will be aggregated to determine Galactic structure in the interstellar medium (ISM) and produce the next-generation electron density model. Fluctuations in density and magnetic field from parsec scales down to about 1000 km cause a number of propagation effects in both radio waves and cosmic rays. Density microstructure appears to include Kolmogorov-like turbulence. The next generation electron-density model, NE2012, will include about double the number of lines of sight with dispersion and scattering measurements and it will be anchored with a much larger number of pulsar parallax distances. The foreground Galactic model is crucial for inferring similar ionized structures in the intergalactic medium (IGM) from scattering measurements on high-z objects. Intergalactic scattering is discussed with reference to distant sources of radio bursts. In particular, the cosmological radio scattering horizon is defined along with its analog for the ISM.

  10. Intergalactic absorption and blazar gamma-ray spectra

    E-print Network

    Persic, Massimo

    2007-01-01

    The distribution of TeV spectral slopes versus redshift for currently known TeV blazars (15 sources with z0.25) is essentially a scatter plot with hardly any hint of a global trend. We suggest that this is the outcome of two combined effects of intergalactic gamma-gamma absorption, plus an inherent feature of the SSC (synchro-self-Compton) process of blazar emission. First, flux dimming introduces a bias that favors detection of progressively more flaring sources at higher redshifts. According to mainstream SSC models, more flaring source states imply sources with flatter TeV slopes. This results in a structured relation between intrinsic TeV slope and redshift. The second effect, spectral steepening by intergalactic absorption, affects sources progressively with distance and effectively wipes out the intrinsic slope-redshift correlation.

  11. Intergalactic absorption and blazar gamma-ray spectra

    E-print Network

    Massimo Persic; Alessandro De Angelis

    2008-03-24

    The distribution of TeV spectral slopes versus redshift for currently known TeV blazars (16 sources with z0.25) is essentially a scatter plot with hardly any hint of a global trend. We suggest that this is the outcome of two combined effects of intergalactic gamma-gamma absorption, plus an inherent feature of the SSC (synchro-self-Compton) process of blazar emission. First, flux dimming introduces a bias that favors detection of progressively more flaring sources at higher redshifts. According to mainstream SSC models, more flaring source states imply sources with flatter TeV slopes. This results in a structured relation between intrinsic TeV slope and redshift. The second effect, spectral steepening by intergalactic absorption, affects sources progressively with distance and effectively wipes out the intrinsic slope-redshift correlation.

  12. High-metallicity, photoionized gas in intergalactic large-scale filaments

    NASA Astrophysics Data System (ADS)

    Aracil, Bastien; Tripp, Todd M.; Bowen, David V.; Prochaska, Jason X.; Chen, Hsiao-Wen; Frye, Brenda L.

    2006-03-01

    We present high-resolution ultraviolet spectra of absorption-line systems towards the low-z quasi-stellar object (QSO) HS 0624+6907 (zQSO= 0.3700). Coupled with ground-based imaging and spectroscopic galaxy redshifts, we find evidence that many of these absorbers do not arise in galaxy haloes but rather are truly intergalactic gas clouds distributed within large-scale structures, and moreover, the gas is cool (T < 105 K) and has relatively high metallicity (Z > 0.9Zsolar). Hubble Space Telescope (HST) Space Telescope Imaging Spectrograph (STIS) data reveal a dramatic cluster of 13 HI Lyman ? (Ly?) lines within a 1000 km s-1 interval at zabs= 0.0635. We find 10 galaxies at this redshift with impact parameters ranging from ?= 135h-170 kpc to 1.37h-170 Mpc. The velocities and velocity spread of the Ly? lines in this complex are unlikely to arise in the individual haloes of the nearby galaxies; instead, we attribute the absorption to intragroup medium gas, possibly from a large-scale filament viewed along its long axis. Contrary to theoretical expectations, this gas is not the shock-heated warm-hot intergalactic medium (WHIM); the width of the Ly? lines all indicate a gas temperature T<< 105 K, and metal lines detected in the Ly? complex also favour photoionized, cool gas. No OVI absorption lines are evident, which is consistent with photoionization models. Remarkably, the metallicity is near-solar, [M/H]=-0.05 +/- 0.4 (2? uncertainty), yet the nearest galaxy which might pollute the intergalactic medium is at least 135h-170 kpc away. Tidal stripping from nearby galaxies appears to be the most likely origin of this highly enriched, cool gas. More than six Abell galaxy clusters are found within 4° of the sight line suggesting that the QSO line of sight passes near a node in the cosmic web. At z~ 0.077, we find absorption systems as well as galaxies at the redshift of the nearby clusters Abell 564 and Abell 559. We conclude that the sight line pierces a filament of gas and galaxies feeding into these clusters. The absorber at zabs= 0.07573 associated with Abell 564/559 also has a high metallicity with [C/H] > -0.6, but again the closest galaxy is relatively far from the sight line (?= 293h-170 kpc). The Doppler parameters and HI column densities of the Ly? lines observed along the entire sight line are consistent with those measured towards other low-z QSOs, including a number of broad (b > 40kms-1) Ly? lines.

  13. Intergalactic magnetic field spectra from diffuse gamma rays

    E-print Network

    Wenlei Chen; Borun D. Chowdhury; Francesc Ferrer; Hiroyuki Tashiro; Tanmay Vachaspati

    2014-12-10

    Non-vanishing parity-odd correlators of gamma ray arrival directions observed by Fermi-LAT indicate the existence of a helical intergalactic magnetic field (Tashiro et al.2013). We successfully test this hypothesis using more stringent cuts of the data, Monte Carlo simulations with Fermi-LAT time exposure information, separate analyses for the northern and southern galactic hemispheres, and confirm predictions made in Tashiro & Vachaspati (2014). With some further technical assumptions, we show how to reconstruct the magnetic helicity spectrum from the parity-odd correlators.

  14. Intergalactic magnetic field spectra from diffuse gamma-rays

    NASA Astrophysics Data System (ADS)

    Chen, Wenlei; Chowdhury, Borun D.; Ferrer, Francesc; Tashiro, Hiroyuki; Vachaspati, Tanmay

    2015-07-01

    Non-vanishing parity-odd correlators of gamma-ray arrival directions observed by Fermi-LAT indicate the existence of a helical intergalactic magnetic field with strength B ˜ 10-14 G on ˜10 Mpc scales. We successfully test this hypothesis using more stringent cuts of the data, Monte Carlo simulations with Fermi-LAT time exposure information, separate analyses for the Northern and Southern galactic hemispheres, and confirm predictions made in Tashiro & Vachaspati. With some further technical assumptions, we show how to reconstruct the magnetic helicity spectrum from the parity-odd correlators.

  15. Intergalactic Extinction of High Energy Gamma-Rays

    NASA Technical Reports Server (NTRS)

    Stecker, F. W.

    1998-01-01

    We discuss the determination of the intergalactic pair-production absorption coefficient as derived by Stecker and De Jager by making use of a new empirically based calculation of the spectral energy distribution of the intergalactic infrared radiation field as given by Malkan and Stecker. We show that the results of the Malkan and Stecker calculation agree well with recent data on the infrared background. We then show that Whipple observations of the flaring gamma-ray spectrum of Mrk 421 hint at extragalactic absorption and that the HEGRA observations of the flaring spectrum of Mrk 501 appear to strongly indicate extragalactic absorption. We also discuss the determination of the y-ray opacity at higher redshifts, following the treatment of Salamon and Stecker. We give a predicted spectrum, with absorption included for PKS 2155-304. This XBL lies at a redshift of 0.12, the highest redshift source yet observed at an energy above 0.3 TeV. This source should have its spectrum steepened by approx. 1 in its spectral index between approx. 0.3 and approx. 3 TeV and should show an absorption cutoff above approx. 6 TeV.

  16. Observational Search for Negative Matter in Intergalactic Voids

    NASA Technical Reports Server (NTRS)

    Forward, Robert L.

    1999-01-01

    Negative matter is a hypothetical form of matter with negative rest mass, inertial mass, and gravitational mass. It is not antimatter. If negative matter could be collected in macroscopic amounts, its negative inertial property could be used to make an continuously operating propulsion system which requires neither energy nor reaction mass, yet still violates no laws of physics. Negative matter has never been observed, but its existence is not forbidden by the laws of physics. We propose that NASA support an extension to an ongoing astrophysical observational effort by da Costa, et al. (1996) which could possibly determine whether or not negative matter exists in the well-documented but little-understood intergalactic voids.

  17. ELT requirements for future observations of the Intergalactic Medium

    E-print Network

    Tom Theuns; Raghunathan Srianand

    2006-01-27

    We summarise the science cases for an ELT that were presented in the parallel session on the intergalactic medium, and the open discussion that followed the formal presentations. Observations of the IGM with an ELT provides tremendous potential for dramatic improvements in current programmes in a very wide variety of subjects. These range from fundamental physics (expansion of the Universe, nature of the dark matter, variation of physical constants), cosmology (geometry of the Universe, large-scale structure), reionisation (ionisation state of the IGM at high redshift>6, to more traditional astronomy, such as the interactions between galaxies and the IGM (metal enrichment, galactic winds and other forms of feedback), and the study of the interstellar medium in high redshift galaxies through molecules. The requirements on ELTs and their instruments for fulfilling this potential are discussed.

  18. Heating of the intergalactic medium due to structure formation

    E-print Network

    Biman Nath; Joseph Silk

    2001-07-20

    We estimate the heating of the intergalactic medium due to shocks arising from structure formation. Heating of the gas outside the collapsed regions, with small overdensities (${n_b \\over {\\bar n_b}}\\ll 200$) is considered here, with the aid of Zel'dovich approximation. We estimate the equation of state of this gas, relating the density with its temperature, and its evolution in time, considering the shock heating due to one-$\\sigma$ density peaks as being the most dominant. We also estimate the mass fraction of gas above a given temperature as a function of redshift. We find that the baryon fraction above $10^6$ K at $z=0$ is $\\sim 10 %$. We estimate the integrated Sunyaev-Zel'dovich distortion from this gas at present epoch to be of order $10^{-6}$.

  19. X-ray constraints on the intergalactic medium

    NASA Technical Reports Server (NTRS)

    Aldcroft, Thomas; Elvis, Martin; Mcdowell, Jonathan; Fiore, Fabrizio

    1994-01-01

    We use ROSAT Position Sensitive Proportional Counter (PSPC) spectra of z approximately equal 3 quasars to constrain the density and temperature of the intergalactic medium (IGM). Strong low-energy cutoffs in PSPC spectra of high-redshift quasars are common. However, the absence of absorption toward some high-redshift quasars can be used to put limits on the possible cosmological density, Omega(sub G), of a hot diffuse intergalactic medium (IGM), via an X-ray Gunn-Peterson test using edge and line opacity in the soft X-rays. The K-edges of oxygen, neon, and carbon and the L-edge of iron produce most of the absorption which is spread out by the redshift of the source. We assume an isotropic, isothermal, nonevolving model of the IGM and calculate the optical depth of this absorption. We find that this test can constrain an enriched IGM at temperatures near 10(exp 5) - 10(exp 6) K, intermediate between the hot IGM ruled out by COBE, and the cold IGM ruled out by the traditional Ly alpha Gunn -Peterson test. Photoionization if the IGM by the ultraviolet and X-ray background has a large effect. We give results for three z approximately equal 3 quasars and discuss how the various trade-offs among temperature, abundance, and backgroud radiation strength affect the limits on Omega (sub G). In addition to the high-redshift case, we discuss techniques for constraining the IGM using X-ray spectra of low-redhift quasars (z approximately equal 0.1 - 0.3). Currently available X-ray spectral data have insufficient energy resolution to constrain the IGM umambiguously, and so expected detection limits for future high-resolution spectrometers are presented. We find that with a large effective area (approximately 2000 sq cm), it is possible to substantially constrain or detect the IGM at the densities which are typically predicted.

  20. Search for emission from warm-hot intergalactic medium

    NASA Astrophysics Data System (ADS)

    Takei, Yoh; Ohashi, Takaya; Sato, Kosuke; Mitsuishi, Ikuyuki; Branchini, Enzo; Ursino, Eugenio; Corsi, Alessandra

    About half of the baryons in the local Universe are not yet observed and are thought to reside in the intergalactic medium at temperatures of 0.1-10 million K and densities of 10-6 -10-4 cm-3 . This is called warm-hot intergalactic medium (WHIM). In this paper, we summarize search for emission from the WHIM, and show prospects with future instruments. Using XIS instrument onboard Suzaku, we searched for redshifted OVII and OVIII WHIM emission lines, in cluster outskirts and superclusters: Shapley supercluster, Sculptor supercluster, A2218, A1413, A2142, A2052, and the Coma cluster. The chance for detecting a signal was estimated to be sufficient to motivate our search, given the relatively high density and high temperature expected for the WHIM in these regions. We did not detect the significant emission, but obtained upper limits in OVII and OVIII emission intensities for these clusters and superclusters. The density of the WHIM was constrained based on the upper limits, which is 200-300 times mean baryon density of the Universe. Future instruments such as microcalorimeters have much higher sensitivity for weak lines. In particular a combination of a microcalorimeter and large grasp (effective area times field of view) telescope is ideal for mapping of the WHIM. We created mock spectra that contain the WHIM, cosmic X-ray background and Galactic emission. Here we present our results concerning detectability and expected 3-d maps of the line emitting regions asssociated to the WHIM, with future missions such as EDGE/XENIA.

  1. X-Ray Emission from the Warm Hot Intergalactic Medium

    E-print Network

    E. Ursino; M. Galeazzi

    2006-04-10

    The number of detected baryons in the Universe at z<0.5 is much smaller than predicted by standard big bang nucleosynthesis and by the detailed observation of the Lyman alpha forest at red-shift z=2. Hydrodynamical simulations indicate that a large fraction of the baryons today is expected to be in a ``warm-hot'' (10^5-10^7K) filamentary gas, distributed in the intergalactic medium. This gas, if it exists, should be observable only in the soft X-ray and UV bands. Using the predictions of a particular hydrodynamic model, we simulated the expected X-ray flux as a function of energy in the 0.1-2 keV band due to the Warm-Hot Intergalactic Medium (WHIM), and compared it with the flux from local and high red-shift diffuse components. Our results show that as much as 20% of the total diffuse X-ray background (DXB) in the energy range 0.37-0.925keV could be due to X-ray flux from the WHIM, 70% of which comes from filaments at redshift z between 0.1 and 0.6. Simulations done using a FOV of 3', comparable with that of Suzaku and Constellation-X, show that in more than 20% of the observations we expect the WHIM flux to contribute to more than 20% of the DXB. These simulations also show that in about 10% of all the observations a single bright filament in the FOV accounts, alone, for more than 20% of the DXB flux. Red-shifted oxygen lines should be clearly visible in these observations.

  2. Parity-odd correlators of diffuse gamma rays and intergalactic magnetic fields

    E-print Network

    Hiroyuki Tashiro; Tanmay Vachaspati

    2014-09-12

    We develop the connection between intergalactic helical magnetic fields and parity odd signatures in the diffuse gamma ray sky. We find that the location and the amplitude of a peak in a parity odd correlator, $Q(R)$, can be used to infer the normal and helical power spectra of the intergalactic magnetic field. When applied to Fermi-LAT data, the amplitude of the observed peak in $Q(R)$ gives $\\sim 10^{-14}~{\\rm G}$ intergalactic magnetic field strength, which is consistent with an earlier independent estimate that only used the peak location (Tashiro et al. 2014). We discuss features in the observed $Q(R)$ that further support the intergalactic magnetic field hypothesis and make predictions for future tests.

  3. The photoheating of the intergalactic medium in synthesis models of the UV background

    NASA Astrophysics Data System (ADS)

    Puchwein, Ewald; Bolton, James S.; Haehnelt, Martin G.; Madau, Piero; Becker, George D.; Haardt, Francesco

    2015-07-01

    We compare cosmological hydrodynamical simulations combined with the homogeneous metagalactic UV background (UVB) of Haardt & Madau (hereafter HM2012) to observations of the Lyman ? forest that are sensitive to the thermal and ionization state of the intergalactic medium (IGM). The transition from optically thick to thin photoheating predicted by the simple one-zone, radiative transfer model implemented by HM2012 predicts a thermal history that is in remarkably good agreement with the observed rise of the IGM temperature at z ˜ 3 if we account for the expected evolution of the volume filling factor of He III. Our simulations indicate that there may be, however, some tension between the observed peak in the temperature evolution and the rather slow evolution of the He II opacities suggested by recent Hubble Space Telescope/Cosmic Origins Spectrograph measurements. The HM2012 UVB also underpredicts the metagalactic hydrogen photoionization rate required by our simulations to match the observed opacity of the forest at z > 4 and z < 2.

  4. Starbursts: Lessons for the Origin and Evolution of Galaxies and the Inter-Galactic Medium

    E-print Network

    Timothy M. Heckman

    1997-08-28

    Starbursts are episodes of intense star-formation that occur in the central regions of galaxies, and dominate the integrated emission from the galaxy. They are a significant component of the present- day universe, being the site of $\\sim$ 25% of the high-mass star- formation. They offer unique `laboratories' for testing our ideas about star-formation, the evolution of high-mass stars, and the physics of the interstellar medium. They serve as local analogs of the processes that were important in the origin and early evolution of galaxies and in the heating and chemical enrichment of the inter-galactic medium. In this contribution I review starbursts from this broad cosmogonical perspective, stressing several key lessons we have learned from starbursts: 1) Violent, transient events play a significant role in the origin and evolution of galaxies. 2) Galaxies do not evolve as `Island Universes': starbursts are triggered by galaxy interactions and produce outflows of hot chemically-enriched gas that `pollute' the inter- galactic medium. 3) Dust dramatically affects of view of high-mass star-formation in starbursts and (probably) in high-redshift galaxies. Throughout this review I emphasize the importance of space-based observations in understanding starbursts.

  5. Electromagnetic Zero Point Field as Active Energy Source in the Intergalactic Medium

    E-print Network

    Alfonso Rueda; Hiroki Sunahata; Bernhard Haisch

    1999-06-16

    For over twenty years the possibility that the electromagnetic zero point field (ZPF) may actively accelerate electromagnetically interacting particles in regions of extremely low particle density (as those extant in intergalactic space (IGS) with n energies. The recent finding by the AGASA collaboration (Phys. Rev. Lett., 81, 1163, 1998) that the CR energy spectrum does not display any signs of the Greisen-Zatsepin-Kuzmin cut-off (that should be present if these CR particles were indeed generated in localized ultrahigh energies CR sources, as e.g., quasars and other highly active galactic nuclei), may indicate the need for an acceleration mechanism that is distributed throughout IGS as is the case with the ZPF. Other unexplained phenomena that receive an explanation from this mechanism are the generation of X-ray and gamma-ray backgrounds and the existence of Cosmic Voids. However recently, a statistical mechanics kind of challenge to the classical (not the quantum) version of the zero-point acceleration mechanism has been posed (de la Pena and Cetto, The Quantum Dice, 1996). Here we briefly examine the consequences of this challenge and a prospective resolution.

  6. Navy Space and Astronautics Orientation.

    ERIC Educational Resources Information Center

    Herron, R. G.

    Fundamental concepts of the spatial environment, technologies, and applications are presented in this manual prepared for senior officers and key civilian employees. Following basic information on the atmosphere, solar system, and intergalactic space, a detailed review is included of astrodynamics, rocket propulsion, bioastronautics, auxiliary…

  7. Heating of Intergalactic Gas and Cluster Scaling Relations

    E-print Network

    Michael Loewenstein

    1999-10-14

    X-ray observations of galaxy groups and clusters are inconsistent with the predictions of the simplest hierarchical clustering models, wherein non-baryonic and baryonic components are assembled together under the sole influence of gravity. These departures are in the sense that the intergalactic medium is hotter and more extended than expected, and become increasingly strong for less massive systems. I model these effects by constructing baseline sequences of hydrostatic polytropic models normalized to observations of high-temperature clusters and numerical simulations, and then transforming them by adding proscribed amounts of heat per particle at the cluster center. I present sequences with a universal value of this heating parameter that simultaneously reproduce recently published observed (gas and total gravitational) mass-temperature and entropy-temperature relations. The required amount of energy injection is consistent with constraints on the number of supernovae needed to account for observed intracluster silicon abundances, provided that energy injection is centrally concentrated. I argue that most of the heating occurred during or after the assembly of the cluster, and not exclusively in pre-collapse proto-cluster fragments.

  8. Legacy HST Spectroscopy of the Low Redshift Intergalactic Medium

    NASA Astrophysics Data System (ADS)

    Impey, Chris

    2005-07-01

    We propose a homogeneous analysis of all HST spectra of quasars and AGN that probe the low redshift intergalactic medium {z < 0.4}. Data taken at moderate resolution with each of the three spectroscopic instruments - FOS, GHRS, and STIS - will be included. The analysis will involve 316 targets, span a total redshift path of 110 and yield an estimated 1500 Lyman-alpha absorbers. In this redshift range, it will incease the number of absorbers by a factor of 15 over the HST Absorption Line Key Project. Data products include co-added and calibrated spectra, continuum fits, absorption line lists, and line identifications, all on a web site that includes hyperlinked information from NED and ADS. About 90% of the sightlines are in regions covered by the SDSS, 2dF and 6dF surveys. This Archive Legacy database will facilitate a range of scientific investigations, including {a} studies of the relationship between luminous baryons in galaxies and diffuse baryons in the IGM, {b} comparisons between the observations and simulations that incorporate gas dynamics, {c} measures of cosmic variance in structure on the largest scales, {d} new tests of the gravitational instability paradigm, {e} accurate determination of the proximity effect at low redshift, and {f} measurements of the chemical enrichment of the IGM. With no prospect of sensitive UV spectroscopy in the forseeable future, this dataset will form part of HST's unique and enduring legacy.

  9. A Search for Intergalactic Globular Clusters in the Local Group

    E-print Network

    Zinn, Graziella di Tullio

    2015-01-01

    The whole Sloan Digital Sky Survey (SDSS, 14,555 deg^2 has been searched for intergalactic globular clusters (IGCs) in the Local Group (LG). Using optical, infrared, and ultraviolet photometric selection criteria and photometric redshifts, the 2.1x10^8 of objects in the SDSS Galaxy Catalogue were reduced to only 183,791 brighter than r_o = 19 that might be GCs. Visual examination of their SDSS images recovered 84 percent of the confirmed GCs in M31 and M33 and yielded 17 new GC candidates, 5 of them of high confidence, which we could confirm as GCs in MegaPrime images from the Canada, France, Hawaii Telescope. These 5 GCs are within M31's halo, but the other 12 candidates are not close to LG galaxies or galaxies within 3 Mpc of the LG. Even though this search covers only one-third of the sky and some GCs could have been missed, it suggests that the LG does not contain a large population of IGCs more luminous than Mv ~ -6. In the direction of the M81 Group, the search yielded five candidate GCs, probable membe...

  10. A COS Survey of the Low-Redshift Intergalactic Medium

    NASA Astrophysics Data System (ADS)

    Danforth, Charles; Pieri, M.; Shull, J. M.; Keeney, B. A.; Stevans, M. L.; Stocke, J. T.; Savage, B. D.; Green, J. C.

    2013-01-01

    In three years of science operations onboard HST, the Cosmic OriginsSpectrograph has generated an archive of far-ultraviolet AGN spectra of unprecedented breadth, depth, and quality. COS was designed to be sensitive to many important diagnostic lines in the far-UV (1135-1800A) in the low-redshift, "local" universe: Lya (z<0.47), Lyb (0.1intergalactic absorption along ~200 extragalactic sight lines. This significant cornerstone of the scientific legacy of COS is at least an order-of-magnitude improvement over previous low-z IGM surveys in total observed pathlength and number of absorbers as well as substantial improvements in sensitivity and uniformity. Of particular interest is the sensitivity of COS to weak and broad absorption. We discuss the scope of and methodology behind the catalog, several initial discoveries, and the overall statistical findings of the survey. Finally, we discuss the new areas of cosmology enabled by this expanded study.

  11. Equilibration processes in the Warm-Hot Intergalactic Medium

    E-print Network

    A. M. Bykov; F. B. S. Paerels; V. Petrosian

    2008-01-07

    The Warm-Hot Intergalactic Medium (WHIM) is thought to contribute about 40-50 % to the baryonic budget at the present evolution stage of the universe. The observed large scale structure is likely to be due to gravitational growth of density fluctuations in the post-inflation era. The evolving cosmic web is governed by non-linear gravitational growth of the initially weak density fluctuations in the dark energy dominated cosmology. Non-linear structure formation, accretion and merging processes, star forming and AGN activity produce gas shocks in the WHIM. Shock waves are converting a fraction of the gravitation power to thermal and non-thermal emission of baryonic/leptonic matter. They provide the most likely way to power the luminous matter in the WHIM. The plasma shocks in the WHIM are expected to be collisionless. Collisionless shocks produce a highly non-equilibrium state with anisotropic temperatures and a large differences in ion and electron temperatures. We discuss the ion and electron heating by the collisionless shocks and then review the plasma processes responsible for the Coulomb equilibration and collisional ionisation equilibrium of oxygen ions in the WHIM. MHD-turbulence produced by the strong collisionless shocks could provide a sizeable non-thermal contribution to the observed Doppler parameter of the UV line spectra of the WHIM.

  12. Can the intergalactic medium cause a rapid drop in Ly? emission at z > 6?

    NASA Astrophysics Data System (ADS)

    Mesinger, Andrei; Aykutalp, Aycin; Vanzella, Eros; Pentericci, Laura; Ferrara, Andrea; Dijkstra, Mark

    2015-01-01

    The large cross-section of the Ly? line makes it a sensitive probe of the ionization state of the intergalactic medium (IGM). Here, we present the most complete study to date of the IGM Ly? opacity, and its application to the redshift evolution of the `Ly? fraction', i.e. the fraction of colour-selected galaxies with a detectable Ly? emission line. We use a tiered approach, which combines large-scale seminumeric simulations of reionization with moderate-scale hydrodynamic simulations of the ionized IGM. This allows us to simultaneously account for evolution in both: (i) the opacity from an incomplete (patchy) reionization, parametrized by the filling factor of ionized regions, QH II; and (ii) the opacity from self-shielded systems in the ionized IGM, parametrized by the average photoionization rate inside H II regions, H II. In contrast to recent empirical models, attenuation from patchy reionization has a unimodal distribution along different sightlines, while attenuation from self-shielded systems is more bimodal. We quantify the average IGM transmission in our (QH II, H II) parameter space, which can easily be used to interpret new data sets. Our new, improved models highly disfavour an evolution in H II as the sole driver of a large change in IGM opacity. Using current observations, we predict that the Ly? fraction cannot drop by more than a factor of ?2 with IGM attenuation alone, even for H II filling factors as low as QH II ? 0.1. Larger changes in the Ly? fraction could result from a co-evolution with galaxy properties. Marginalizing over H II, we find that current observations constrain QH II(z ? 7) ? 0.6, at a 68 per cent confidence level (CL). However, all of our parameter space is consistent with observations at 95 per cent CL, highlighting the need for larger observational samples at z ? 6.

  13. Multifrequency survey of the intergalactic cloud in the M96 group

    SciTech Connect

    Schneider, S.E.; Skrutskie, M.F.; Hacking, P.B.; Young, J.S.; Dickman, R.L.

    1989-03-01

    The intergalactic cloud of neutral hydrogen in the M96 group are examined for signs of emission over a wide range of frequencies, from radio waves to X rays. Past or present stellar activity in the gas might have been expected to produce detectable visual infrared, CO, OH, or radio recombination-line emission. None was detected. The limits are used to study physical conditions in the intergalactic gas. In particular, B and V band limits on starlight and IRAS limits on the presence of dust strongly constrain the presence of stars or stellar by-products. However, given the uncertainties about physical conditions in the intergalactic environment, it is difficult to rule out entirely the presence of stellar-processed materials. Results of neutral hydrogen mapping from a large-scale survey of the intergalactic cloud and surrounding region are also presented. These observations confirm that the gas is confined to a large ringlike structure. The simplest interpretation remains that the intergalactic gas in Leo is primordial. 36 references.

  14. Warm-Hot Intergalactic Medium Associated with the Coma Cluster

    E-print Network

    Yoh Takei; J. Patrick Henry; Alexis Finoguenov; Kazuhisa Mitsuda; Takayuki Tamura; Ryuichi Fujimoto; Ulrich G. Briel

    2006-10-13

    We present our XMM-Newton RGS observations of X Comae, an AGN behind the Coma cluster. We detect absorption by NeIX and OVIII at the redshift of Coma with an equivalent width of 3.3+/-1.8 eV and 1.7+/-1.3 eV, respectively (90% confidence errors or 2.3 sigma and 1.9 sigma confidence detections determined from Monte Carlo simulations). The combined significance of both lines is 3.0 sigma, again determined from Monte Carlo simulations. The same observation yields a high statistics EPIC spectrum of the Coma cluster gas at the position of X Comae. We detect emission by NeIX with a flux of 2.5+/-1.2 x 10^-8 photons cm^-2 s^-1 arcmin^-2 (90% confidence errors or 3.4 sigma confidence detection). These data permit a number of diagnostics to determine the properties of the material causing the absorption and producing the emission. Although a wide range of properties is permitted, values near the midpoint of the range are T = 4 x 10^6 K, n_H = 6 x 10^-6 cm^-3 corresponding to an overdensity with respect to the mean of 32, line of sight path length through it 41 Z/Zsolar^-1 Mpc where Z/Zsolar is the neon metallicity relative to solar. All of these properties are what has been predicted of the warm-hot intergalactic medium (WHIM), so we conclude that we have detected the WHIM associated with the Coma cluster.

  15. Metallicity of the intergalactic medium using pixel statistics: III. Silicon

    E-print Network

    Anthony Aguirre; Joop Schaye; Tae-Sun Kim; Tom Theuns; Michael Rauch; Wallace L. W. Sargent

    2004-01-13

    (Modified) We study the abundance of silicon in the intergalactic medium by analyzing the statistics of SiIV, CIV, and HI pixel optical depths in a sample of 19 high-quality quasar absorption spectra spanning redshifts z ~ 2 - 4, which we compare to realistic spectra drawn from a hydrodynamical simulation. We find that silicon is highly overabundant relative to carbon and that the scatter in Si/C is much smaller than that in C/H, implying a common origin for Si and C. The inferred [Si/C] depends upon the shape of the UV background (UVB) (harder backgrounds leading to higher [Si/C]), ranging from [Si/C] ~ 1.5 for a quasar-only UVB, to [Si/C] ~ 0.25 for a UVB including both galaxies and an artificial softening. For our fiducial UVB, which includes both quasars and galaxies, we find [Si/C]=0.77 +/- 0.05, with a possible systematic error of ~ 0.1 dex. There is no evidence for evolution in [Si/C] and the data are inconsistent with previous claims of a sharp change in the SiIV/CIV ratio (or the UVB) at z ~ 3. Comparisons with low-metallicity halo stars and nucleosynthetic yields suggest that either our fiducial UVB is too hard or that supermassive Pop III stars might have to be included. The inferred [Si/C] corresponds to a contribution to the cosmic Si abundance of [Si/H] = -2.0, a significant fraction of all Si production expected by z ~ 3.

  16. THEIA: Telescope for Habitable Exoplanets and Interstellar/Intergalactic Astronomy

    NASA Astrophysics Data System (ADS)

    Spergel, David N.; Kasdin, J.; Belikov, R.; Atcheson, P.; Beasley, M.; Calzetti, D.; Cameron, B.; Copi, C.; Desch, S.; Dressler, A.; Ebbets, D.; Egerman, R.; Fullerton, A.; Gallagher, J.; Green, J.; Guyon, O.; Heap, S.; Jansen, R.; Jenkins, E.; Kasting, J.; Keski-Kuha, R.; Kuchner, M.; Lee, R.; Lindler, D.; Linfield, R.; Lisman, D.; Lyon, R.; Malhotra, S.; Mathews, G.; McCaughrean, M.; Mentzel, J.; Mountain, M.; NIkzad, S.; O'Connell, R.; Oey, S.; Padgett, D.; Parvin, B.; Procashka, J.; Reeve, W.; Reid, I. N.; Rhoads, J.; Roberge, A.; Saif, B.; Scowen, P.; Seager, S.; Seigmund, O.; Sembach, K.; Shaklan, S.; Shull, M.; Soummer, R.

    2009-01-01

    By combining an occultor with a 4-meter optical/ultraviolet telescope, THEIA (Telescope for Habiatable Earths and Interstellar/Intergalactic Astronomy) will conduct an observational program that address many of the most exciting questions in astrophysics. The telescope is an on-axis telescope with a MgF-coated primary and a LiF-coated secondary. This hybrid approach allows reasonable through-put in the UV without the need to coat a large piimary with LiF. The coronagraph/occultor system is also a hybrid that aims to reduce the requirements on each approach. The telescope feeds a rich instrument complement. The eXtrasolar Planet Characterizer (XPC) baseline instruments are three narrow-field cameras for the UV (0.25-4.0 microns), blue (0.4-0.7 microns) and red (0.7-1.0 microns) with filters, and an integral field spectrograph (IFS) operating in the red. A wide-field high-resolution camera (Star Formation Camera) operating with a blue (190--517nm) and a red (517--1075nm) channel will conduct a comprehensive and systematic study of the astrophysical processes and environments relevant for the births and life cycles of stars and their planetary systems. A UV high-resolution spectrograph (UVS) with R=30,000-100,000 in the far-UV (1000-1700 A) and near-UV (1700-3000 A) will strengthen the foundations of observational cosmology by examining the cosmic web (IGM), its interactions with galaxies, and its enrichment with the products of stellar and galactic evolution. This mission has two basic opseration modes. While the occultor is moving from target star to target star, the telescope carries out an exciting program of general astrophysics. While the occultor is on target, it will characterize the key properties of a detected planet and deeply image adjacent fields in parallel mode.

  17. Absorption of Very High Energy Gamma-Rays by Intergalactic Infrared Radiation: A New Determination

    E-print Network

    F. W. Stecker; O. C. De Jager

    1998-04-20

    We present a new calculation of the intergalactic gamma-ray absorption coefficient as a function of both energy and redshift. In reexamining this problem, we make use of a new, empirically based calculation (as opposed to previous model calculations) of the intergalactic infrared radiation field. We find smaller opacities than those given previously (Stecker & De Jager 1997). We apply our results to the new observations of the flaring gamma-ray spectra of Mrk421 and Mrk501, both at a redshift of apx. 0.03. Our new calculations indicate that there should be no significant curvature in the spectra of these sources for energies below 10 TeV, as indicated by recent observations. However, the intrinsic spectra of these sources should be harder by apx. 0.2 to 0.45 in the spectral index in the 1 to 10 TeV range with an intergalactic absorption cutoff above apx. 20 TeV.

  18. Intergalactic H_2 Photodissociation and the Soft UV Background Produced by Population III Objects

    E-print Network

    Benedetta Ciardi; Andrea Ferrara; Tom Abel

    1999-04-09

    We study the effects of the ionizing and dissociating photons produced by PopIII objects on the surrounding intergalactic medium. We find that the typical size of a H_2 photodissociated region, R_d ~ 1-5 kpc, is smaller than the mean distance between sources at z ~ 20-30, but larger than the ionized region by a factor depending on the detailed properties of the emission spectrum. This implies that clearing of intergalactic H_2 occurs before reionization of the universe is complete. In the same redshift range, the soft-UV background in the Lyman-Werner bands, when the intergalactic H and H_2 opacity is included, is found to be J_LW ~ 1d-30 - 1d-27 erg cm^{-2} s^{-1} Hz^{-1}. This value is well below the threshold required for the negative feedback of PopIII objects on the subsequent galaxy formation to be effective in that redshift range.

  19. The Temperature-Density Relation in the Intergalactic Medium at Redshift langzrang = 2.4

    NASA Astrophysics Data System (ADS)

    Rudie, Gwen C.; Steidel, Charles C.; Pettini, Max

    2012-10-01

    We present new measurements of the temperature-density (T-?) relation for neutral hydrogen in the 2.0 < z < 2.8 intergalactic medium (IGM) using a sample of ~6000 individual H I absorbers fitted with Voigt profiles constrained in all cases by multiple Lyman series transitions. We find model-independent evidence for a positive correlation between the column density of H I (N H I ) and the minimum observed velocity width of absorbers (b min). With minimal interpretation, this implies that the T-? relation in the IGM is not "inverted," contrary to many recent studies. Fitting b min as a function of N H I results in line-width-column-density dependence of the form b min = b 0(N H I /N H I,0)?-1 with a minimum line width at mean density (\\rho /\\bar{\\rho }= 1, N_H\\,\\mathsc{i, 0} = 10^{13.6} cm-2) of b 0 = 17.9 ± 0.2 km s-1 and a power-law index of (? - 1) = 0.15 ± 0.02. Using analytic arguments, these measurements imply an "equation of state" for the IGM at langzrang = 2.4 of the form T=T_0 \\left(\\rho /\\bar{\\rho }\\right)^{\\gamma -1} with a temperature at mean density of T 0 = [1.94 ± 0.05] × 104 K and a power-law index (? - 1) = 0.46 ± 0.05. Based on data obtained at the W. M. Keck Observatory, which is operated as a scientific partnership among the California Institute of Technology, the University of California, and the National Aeronautics and Space Administration, and was made possible by the generous financial support of the W. M. Keck Foundation.

  20. The Detection of Oxygen in the Low-Density Intergalactic Medium

    NASA Astrophysics Data System (ADS)

    Schaye, Joop; Rauch, Michael; Sargent, Wallace L. W.; Kim, Tae-Sun

    2000-09-01

    The abundances of metals in the intergalactic medium (IGM) can be used to constrain the amount of star formation at high redshift and the spectral shape of the ionizing background radiation. For both purposes, it is essential to measure the abundances in regions of low density, away from local sources of metals and ionizing photons. Here we report the first detection of O VI in the low-density IGM at high redshift. We perform a pixel-by-pixel search for O VI absorption in eight high-quality quasar spectra spanning the redshift range z=2.0-4.5. At 2<~z<~3, we clearly detect O VI in the form of a positive correlation between the H I Ly? optical depth and the optical depth in the corresponding O VI pixel, down to ?HI~10-1. This is an order of magnitude lower in ?HI than the best C IV measurements can probe, and it constitutes the first clear detection of metals in underdense gas. The nondetection of O VI at z>3 is consistent with the enhanced photoionization from a hardening of the UV background below z~3 but could also be caused by the high level of contamination from Lyman series lines. Part of the data presented herein was obtained at the W. M. Keck Observatory, which is operated as a scientific partnership among the California Institute of Technology, the University of California, and the National Aeronautics and Space Administration. The W. M. Keck Observatory was made possible by the generous financial support of the W. M. Keck Foundation.

  1. Tracing the Cosmic Metal Evolution in the Low-redshift Intergalactic Medium

    NASA Astrophysics Data System (ADS)

    Shull, J. Michael; Danforth, Charles W.; Tilton, Evan M.

    2014-11-01

    Using the Cosmic Origins Spectrograph aboard the Hubble Space Telescope, we measured the abundances of six ions (C III, C IV, Si III, Si IV, N V, and O VI) in the low-redshift (z <= 0.4) intergalactic medium (IGM). Both C IV and Si IV have increased in abundance by a factor of ~10 from z ? 5.5 to the present. We derive ion mass densities, ?ion ? ?ion?cr, with ?ion expressed relative to the closure density. Our models of mass-abundance ratios, (Si III/Si IV) = 0.67+0.35-0.19, (C III/C IV) = 0.70+0.43-0.20, and (? C \\scriptsize{III} + ? C \\scriptsize{IV}) / (? _Si \\scriptsize{III} + ? _Si \\scriptsize{IV}) = 4.9+2.2-1.1, are consistent with the photoionization parameter log U = -1.5 ± 0.4, hydrogen photoionization rate ?H = (8 ± 2) × 10-14 s-1 at z < 0.4, and specific intensity I 0 = (3 ± 1) × 10-23 erg cm-2 s-1 Hz-1 sr-1 at the Lyman limit. Consistent ionization corrections for C and Si are scaled to an ionizing photon flux ?0 = 104 cm-2 s-1, baryon overdensity ? b ? 200 ± 50, and "alpha-enhancement" (Si/C enhanced to three times its solar ratio). We compare these metal abundances to the expected IGM enrichment and abundances in higher photoionized states of carbon (C V) and silicon (Si V, Si VI, and Si VII). Our ionization modeling infers IGM metal densities of (5.4 ± 0.5) × 105 M ? Mpc-3 in the photoionized Ly? forest traced by the C and Si ions and (9.1 ± 0.6) × 105 M ? Mpc-3 in hotter gas traced by O VI. Combining both phases, the heavy elements in the IGM have mass density ? Z = (1.5 ± 0.8) × 106 M ? Mpc-3 or ? Z ? 10-5. This represents 10% ± 5% of the metals produced by (6 ± 2) × 108 M ? Mpc-3 of integrated star formation with yield ym = 0.025 ± 0.010. The missing metals at low redshift may reside within galaxies and in undetected ionized gas in galactic halos and circumgalactic medium. Based on observations made with the NASA/ESA Hubble Space Telescope, obtained from the data archive at the Space Telescope Science Institute. STScI is operated by the Association of Universities for Research in Astronomy, Inc., under NASA Contract NAS5-26555.

  2. H i GAS IN HIGHER DENSITY REGIONS OF THE INTERGALACTIC MEDIUM1 Toru Misawa,2

    E-print Network

    Iye, Masanori

    H i GAS IN HIGHER DENSITY REGIONS OF THE INTERGALACTIC MEDIUM1 Toru Misawa,2 David Tytler,3, we attempt to separate H i absorption lines in quasar spectra into two categories: higher density lines (HDLs) and lower density lines (LDLs), and we discuss the difference in their physical properties

  3. Confirmation of X-ray Absorption by Warm-hot Intergalactic Medium in the Sculptor Wall

    E-print Network

    Fang, Taotao

    In a previous paper, we reported a 3? detection of an absorption line from the warm-hot intergalactic medium (WHIM) using the Chandra and XMM X-ray grating spectra of the blazar H2356-309, the sight line of which intercepts ...

  4. Telescope for Habitable Exoplanets and Interstellar/Intergalactic Astronomy

    E-print Network

    Industry Partners: Lockheed Martin Missiles and Space, ITT Space Systems, LLC, Ball Aerospace NASA Partners Flight Center University Partners: Arizona State University, Caltech, Case Western Reserve University? How frequently do solar systems form and survive? How do stars and galaxies form and evolve? How

  5. Intergalactic Photon Spectra from the Far-IR to the UV Lyman Limit for 0 < z < 6 and the Optical Depth of the Universe to High-Energy Gamma Rays

    NASA Technical Reports Server (NTRS)

    Stecker, F. W.; Malkan, M. A.; Scully, S. T.

    2006-01-01

    We calculate the intergalactic photon density as a function of both energy and redshift for 0intergalactic photon densities to extend previous work on the absorption of high-energy Gamma-rays in intergalactic space owing to interactions with low-energy photons and the 2.7 K cosmic microwave background radiation. We calculate the optical depth of the universe, Tau , for Gamma-rays having energies from 4 GeV to 100 TeV emitted by sources at redshifts from 0 to 5. We also give an analytic fit with numerical coefficients for approximating (E(Gamma), z). As an example of the application of our results, we calculate the absorbed spectrum of the blazar PKS 2155-304 at z=0.117 and compare it with the spectrum observed by the HESS air Cerenkov Gamma-ray telescope array.

  6. Space.

    ERIC Educational Resources Information Center

    Web Feet K-8, 2001

    2001-01-01

    This annotated subject guide to Web sites and additional resources focuses on space and astronomy. Specifies age levels for resources that include Web sites, CD-ROMS and software, videos, books, audios, and magazines; offers professional resources; and presents a relevant class activity. (LRW)

  7. Intergalactic Hydrogen Clouds at Low Redshift: Connections to Voids and Dwarf Galaxies

    NASA Technical Reports Server (NTRS)

    Shull, J. Michael; Stocke, John T.; Penton, Steve

    1996-01-01

    We provide new post-COSTAR data on one sightline (Mrk 421) and updated data from another (I Zw 1) from our Hubble Space Telescope (HST) survey of intergalactic Ly(alpha) clouds located along sightlines to four bright quasars passing through well-mapped galaxy voids (16000 km/s pathlength) and superclusters (18000 km/s). We report two more definite detections of low-redshift Ly(alpha) clouds in voids: one at 3047 km/s (heliocentric) toward Mrk 421 and a second just beyond the Local Supercluster at 2861 km/s toward I Zw 1, confirming our earlier discovery of Ly(alpha) absorption clouds in voids (Stocke et al., ApJ, 451, 24). We have now identified ten definite and one probable low-redshift neutral hydrogen absorption clouds toward four targets, a frequency of approximately one absorber every 3400 km/s above 10(exp 12.7/sq cm column density. Of these ten absorption systems, three lie within voids; the probable absorber also lies in a void. Thus, the tendency of Ly(alpha) absorbers to 'avoid the voids' is not as clear as we found previously. If the Ly(alpha) clouds are approximated as homogeneous spheres of 100 kpc radius, their masses are approximately 10(exp 9)solar mass (about 0.01 times that of bright L* galaxies) and they are 40 times more numerous, comparable to the density of dwarf galaxies and of low-mass halos in numerical CDM simulations. The Ly(alpha) clouds contribute a fraction Omega(sub cl)approximately equals 0.003/h(sub 75) to the closure density of the universe, comparable to that of luminous matter. These clouds probably require a substantial amount of nonbaryonic dark matter for gravitational binding. They may represent extended haloes of low-mass protogalaxies which have not experienced significant star formation or low-mass dwarf galaxies whose star formation ceased long ago, but blew out significant gaseous material.

  8. Hubble/COS Observations of Intergalactic Gas Toward PKS 0405-123

    NASA Astrophysics Data System (ADS)

    Shull, J. Michael; Danforth, C.; Froning, C.; Green, J.; Keeney, B.; Stocke, J.; Yao, Y.; Savage, B.; Narayanan, A.; Sembach, K.

    2010-01-01

    We present an overview of far-UV Hubble Space Telescope observations (1150-1780 A, at 17 km/s resolution) taken by the Cosmic Origins Spectrograph (COS) of the QSO PKS 0405-123 at redshift zem = 0.5726 and FUV flux 3.5x10-14 erg/s/cm2/A. This spectrum illustrates the the power of COS for studying metal-enriched gas between the galaxies, distributed throughout the multiphase intergalactic medium (IGM). We used 7 orbits with 9 FP-split positions, obtained S/N = 35-45 over much of the G130M band (1150-1440 A), and detected numerous absorption features of hydrogen (Lya, Lyb) and heavy-element probes of metallicity. Ions that can be studied include lines (O VI, N V, Ne VIII) sensitive to hot gas produced by strong shocks produced in gravitational inflows to the Cosmic Web, in circumgalactic gas, and in galactic winds. The high S/N allows a search for broad Ly-alpha possibly associated with O VI in hot gas (105 to 106 K). This sight line also intercepts a high-velocity cloud seen in Si III at 110-170 km/s (LSR) and b = -37.55 in the Galactic halo. In the absorption system at z = 0.495, the Ne VIII doublet (770.41, 780.32 A) shifts into the COS band, allowing us to probe the warm-hot IGM at log T = 5.5-6.0, several times deeper than previous (STIS) studies (Prochaska et al. 2004; Howk et al. 2009). In other posters, members of the COS science team describe the detection of O VI absorbers at redshifts z = 0.16710, 0.18292, 0.36156, 0.36332, and 0.49501, including a Lyman Limit system at z = 0.16710 with log N(HI) = 16.45 +/- 0.05. The high S/N observations allow us to measure important ions previously not detected and to evaluate the kinematical relationships and physical conditions among the detected ions.

  9. The Carbon Content of Intergalactic Gas at Z=4.25 and Its Evolution toward Z=2.4

    E-print Network

    Simcoe, Robert A.

    This paper presents ionization-corrected measurements of the carbon abundance in intergalactic gas at 4.0 < z < 4.5, using spectra of three bright quasars obtained with the Magellan Inamori Kycocera Echelle spectrograph ...

  10. Apparent magnitudes of high redshift Type 1a supernovae and intergalactic graphite whiskers

    NASA Astrophysics Data System (ADS)

    Wickramasinghe, N. C.; Wickramasinghe, J. T.

    2008-09-01

    The concept of a Universe undergoing an acceleration in its expansion rate and predicating the existence of dark energy is based on observed deficits in brightness of Type 1a supernovae at high redshifts, amounting to ? m˜0.3 0.5. We show that the effect of intergalactic graphite whiskers of radii in the general range 0.03 0.07 ?m and lengths in excess of ˜5 ?m will be to mimic the effects of dark energy in the redshift magnitude relation for Type 1a supernovae. The mean intergalactic density of whiskers required for such an effect is ˜3×10-34 g cm-3, about 10-5 of the critical closure density.

  11. The intergalactic medium - Initial and boundary conditions for galaxy and primeval star formation

    NASA Technical Reports Server (NTRS)

    Giroux, Mark L.; Shapiro, Paul R.

    1990-01-01

    New detailed numerical calculations are presented of the evolution of the intergalactic medium (IGM) in a post recombination Friedmann universe, including a solution of the nonequilibrium rate equations for the ionization and recombination of H and He, the energy equation, and the equation of radiative transfer. The implications of this study for the characteristic mass scale and the epoch of gravitational collapse for the average 'first' star-forming clouds are discussed. The star-formation rate and associated metallicity generation implied if the IGM is fully ionized by starlight by redshift greater than 4 as suggested by recent interpretations of the Gunn-Peterson effect are examined. It is shown that the relative strengths of metal lines from a quasar absorption-line Lyman limit system cloud at z = 3 photoionized by the present intergalactic UV radiation background are compatible with the observations, at least for background sources of either AGN-type or star-forming galaxy spectra.

  12. Probing Intergalactic Magnetic Fields in the GLAST Era through Pair Echo Emission from TeV Blazars

    NASA Astrophysics Data System (ADS)

    Murase, Kohta; Takahashi, Keitaro; Inoue, Susumu; Ichiki, Kiyomoto; Nagataki, Shigehiro

    2008-10-01

    More than a dozen blazars are known to be emitters of multi-TeV gamma rays, often with strong and rapid flaring activity. By interacting with photons of the cosmic microwave and infrared backgrounds, these gamma rays inevitably produce electron-positron pairs, which in turn radiate secondary inverse Compton gamma rays in the GeV-TeV range with a characteristic time delay that depends on the properties of the intergalactic magnetic field (IGMF). For sufficiently weak IGMF, such ``pair echo'' emission may be detectable by the Gamma-ray Large Area Space Telescope (GLAST), providing valuable information on the IGMF. We perform detailed calculations of the time-dependent spectra of pair echoes from flaring TeV blazars such as Mrk 501 and PKS 2155-304, taking proper account of the echo geometry and other crucial effects. In some cases, the presence of a weak but nonzero IGMF may enhance the detectability of echo. We discuss the quantitative constraints that can be imposed on the IGMF from GLAST observations, including the case of nondetections.

  13. Studies of X-ray clusters of galaxies/intergalactic plasmas

    NASA Technical Reports Server (NTRS)

    Scott, J. S.

    1984-01-01

    Intergalactic plasmas were investigated from both an observational and theoretical point of view. A multiobject spectrometer, the MX spectrograph was used to obtain detailed dynamical information on clusters of galaxies; this information was then compared with X ray emission from hot gas in these clusters. Several spectra of galaxies are presented, and data reduction of the spectra was discussed. The existence of quasar winds in Seyfert galaxies and the interaction between such a wind and the interstellar medium also were considered.

  14. High-metallicity, photoionized gas in intergalactic large-scale filaments

    Microsoft Academic Search

    Bastien Aracil; Todd M. Tripp; David V. Bowen; Jason X. Prochaska; Hsiao-Wen Chen; Brenda L. Frye

    2006-01-01

    We present high-resolution ultraviolet spectra of absorption-line systems towards the low-z quasi-stellar object (QSO) HS 0624+6907 (zQSO= 0.3700). Coupled with ground-based imaging and spectroscopic galaxy redshifts, we find evidence that many of these absorbers do not arise in galaxy haloes but rather are truly intergalactic gas clouds distributed within large-scale structures, and moreover, the gas is cool (T < 105

  15. Apparent magnitudes of high redshift Type 1a supernovae and intergalactic graphite whiskers

    Microsoft Academic Search

    N. C. Wickramasinghe

    2008-01-01

    The concept of a Universe undergoing an acceleration in its expansion rate and predicating the existence of dark energy is\\u000a based on observed deficits in brightness of Type 1a supernovae at high redshifts, amounting to ? m?0.3–0.5. We show that the\\u000a effect of intergalactic graphite whiskers of radii in the general range 0.03–0.07 ?m and lengths in excess of ?5 ?m will

  16. Apparent magnitudes of high redshift Type 1a supernovae and intergalactic graphite whiskers

    Microsoft Academic Search

    N. C. Wickramasinghe; J. T. Wickramasinghe

    2008-01-01

    The concept of a Universe undergoing an acceleration in its expansion rate and predicating the existence of dark energy is based on observed deficits in brightness of Type 1a supernovae at high redshifts, amounting to Delta m˜0.3 0.5. We show that the effect of intergalactic graphite whiskers of radii in the general range 0.03 0.07 mum and lengths in excess

  17. TeV Gamma-Ray Absorption and the Intergalactic Infrared Background

    E-print Network

    F. W. Stecker

    2001-01-12

    In this paper, I will take a synoptic approach to determining the intergalactic infrared radiation field (IIRF). This approach draws on both the multi-TeV gamma-ray observations and the infrared background observations and relates them via the semi-empirical modelling method of Malkan and Stecker. I discuss the evidence for an intergalactic infrared background obtained by an analysis of the HEGRA observations of the high energy gamma-ray spectrum of Mrk 501 and from constraints from Mrk 421 deduced from the Whipple air Cherenkov telescope results. I will show that this evidence is in accord with the predictions made by Malkan and Stecker for the intergalactic infrared spectral energy distribution produced by galaxies. The Malkan-Stecker predictions are also in excellent agreement with mid- and far infrared galaxy counts. However, there may be potential problems relating these predictions with the results of the analysis of COBE-DIRBE far infrared data. The gamma-ray and COBE-DIRBE observations may also need to be reconciled. I will discuss possible ways to resolve this situation including a partial nullification of the $\\gamma$-ray absorption process which can hypothetically occur if Lorentz invariance is broken.

  18. Gamma-ray observations of blazars and the intergalactic magnetic field spectrum

    NASA Astrophysics Data System (ADS)

    Caprini, C.; Gabici, S.

    2015-06-01

    Very high-energy observations of blazars can be used to constrain the strength of the intergalactic magnetic field. A simplifying assumption which is often made is that of a magnetic field of constant strength composed of randomly oriented and identical cells. In this paper, we demonstrate that a more realistic description of the structure of the intergalactic magnetic field is indeed needed. If such a description is adopted, the observational bounds on the field strength are significantly affected in the limit of short field correlation lengths: in particular, they acquire a dependence on the magnetic field power spectrum. In the case of intergalactic magnetic fields which are generated causally, for which the magnetic field large-scale spectral index is nB?2 and even, the observational lower bound becomes more constraining by about a factor of 3. If instead -3

  19. INTERGALACTIC GAS IN GROUPS OF GALAXIES: IMPLICATIONS FOR DWARF SPHEROIDAL FORMATION AND THE MISSING BARYONS PROBLEM

    SciTech Connect

    Freeland, E. [George P. and Cynthia W. Mitchell Institute for Fundamental Physics and Astronomy, Department of Physics and Astronomy, Texas A and M University, College Station, TX 77843 (United States); Wilcots, E., E-mail: freeland@physics.tamu.edu, E-mail: ewilcots@astro.wisc.edu [Department of Astronomy, University of Wisconsin, Madison, WI 53706 (United States)

    2011-09-10

    Radio galaxies with bent jets are predominantly located in groups and clusters of galaxies. We use bent-double radio sources, under the assumption that their jets are bent by ram pressure, to probe intragroup medium (IGM) gas densities in galaxy groups. This method provides a direct measurement of the intergalactic gas density and allows us to probe intergalactic gas at large radii and in systems whose IGM is too cool to be detected by the current generation of X-ray telescopes. We find gas with densities of 10{sup -3} to 10{sup -4} cm{sup -3} at group radii from 15 to 700 kpc. A rough estimate of the total baryonic mass in intergalactic gas is consistent with the missing baryons being located in the IGM of galaxy groups. The neutral gas will be easily stripped from dwarf galaxies with total masses of 10{sup 6}-10{sup 7} M{sub sun} in the groups studied here. Indications are that intragroup gas densities in less-massive systems like the Local Group should be high enough to strip gas from dwarfs like Leo T and, in combination with tides, produce dwarf spheroidals.

  20. Constrainingquasar and intergalactic medium properties through bubble detection in redshifted 21-cm maps

    NASA Astrophysics Data System (ADS)

    Majumdar, Suman; Bharadwaj, Somnath; Choudhury, T. Roy

    2012-11-01

    The infrared detection of a z > 7 quasar has opened up a window to directly probe the intergalactic medium (IGM) during the epoch of reionization. It is anticipated that future observations will yield more quasars extending to higher redshifts. In this paper, we theoretically consider the possibility of detecting the ionized bubble around a z = 8 quasar using targeted redshifted 21-cm observations with the GMRT. The apparent shape and size of the ionized bubble, as seen by a distant observer, depends on the parameters N? phs /C, xH i /c and ?Q, where N? phs and ?Q are, respectively, the ionizing photon emission rate and age of the quasar, and xH i and C are, respectively, the neutral fraction and clumping factor of the IGM. The 21-cm detection of an ionized bubble, thus, holds the promise of allowing us to probe the quasar and IGM properties at z = 8. In this work we have analytically calculated the apparent shape and size of a quasar's ionized bubble assuming a uniform IGM and ignoring other ionizing sources besides the quasar, and used this as a template for matched-filter bubble search with the GMRT visibility data. We have assumed that N? phs is known from the observed infrared spectrum, and C = 30 from theoretical considerations, which gives us the two free parameters xH i and ?Q for bubble detection. Considering 1000'h of observation, we find that there is a reasonably large region of parameter space bounded within (xH i , (?Q/107 yr ))=(1.0, 0.5) and (0.2, 7.0) where a 3? detection is possible if (N? phs /1057 s-1)=3. The available region increases if N? phs is larger, whereas we need xH i ?0.4 and (?Q/107 yr )?2.0 if (N? phs /1057 s-1)=1.3. Considering parameter estimation, we find that in many cases it will be possible to quite accurately constrain ?Q and place a lower limit on xH i with 1000'h of observation, particularly if the bubble is in the early stage of growth and we have a very luminous quasar or a high neutral fraction. Deeper follow-up observations (4000 and 9000'h) can be used to further tighten the constraints on ?Q and xH i . We find that the estimated xH i is affected by uncertainty in the assumed value of C. The quasar's age ?Q however is robust and is unaffected by the uncertainty in C. The presence of other ionizing sources and inhomogeneities in the IGM distort the shape and size of the quasar's ionized bubble. This is a potential impediment for bubble detection and parameter estimation. We have used the seminumerical technique to simulate the apparent shape and size of quasar ionized bubbles incorporating these effects. If we consider a 9000'h of observation with the GMRT, we find that the estimated parameters ?Q and xH i are expected to be within the statistical uncertainties.

  1. Preface: Special Session SpS4 New era for studying interstellar and intergalactic magnetic fields

    NASA Astrophysics Data System (ADS)

    Montmerle, Thierry

    2015-03-01

    Magnetic fields dominate the universal energy balance on a wide variety of spatial scales; preserving life on Earth from extinction by cosmic rays, regulating star formation in giant molecular clouds, regulating the enrichment of the intergalactic medium by galactic winds and possibly regulating the growth of individual galaxies and filaments of galaxies. The structure of magnetic fields is determined by ubiquitous astrophysical turbulence and critically affects transport processes, including propagation and acceleration of cosmic rays and transfer of heat. Turbulent magnetic fields play an important role in magnetic field generation via dynamo processes, and must be understood to separate galactic foregrounds from the Cosmic Microwave Background signal.

  2. Photon-Axion Conversion in Intergalactic Magnetic Fields and Cosmological Consequences

    NASA Astrophysics Data System (ADS)

    Mirizzi, Alessandro; Raffelt1, Georg G.; Serpico, Pasquale D.

    Photon-axion conversion induced by intergalactic magnetic fields causes an apparent dimming of distant sources, notably of cosmic distance indicators such as supernovae of type Ia (SNe Ia). We review the impact of this mechanism on the luminosity-redshift relation of SNe Ia, on the dispersion of quasar spectra, and on the spectrum of the cosmic microwave background. The original idea of explaining the apparent dimming of distant SNe Ia without cosmic acceleration is strongly constrained by these arguments. However, the cosmic equation of state extracted from the SN Ia luminosity-redshift relation remains sensitive to this mechanism. For example, it can mimic phantom energy.

  3. The Warm-Hot Intergalactic Medium: Past, Present and Bright Future

    NASA Astrophysics Data System (ADS)

    Nicastro, F.

    2006-08-01

    In the first part of my talk, I will summarize the current evidence of the Warm-Hot Intergalactic Medium, showing Chandra and XMM-Newton detections of this important baryonic component of the local Universe, along four different lines of sight. I will then dedicate the second half of the talk to future prospects for WHIM studies. I will show spectral simulations performed with the baseline Constellation-X gratings and XEUS calorimeters, and will also present the science case and WHIM spectral simulations for a mid-size dedicated mission concept, called Pharos. Pharos will allow us to efficiently X-ray the intergalactic medium at very high spectral resolution (R > 3000) and in the soft X-ray band (0.08-1.5 keV), along hundreds of lines of sight, in less than 5 years, exploiting the large fluences of GRB X-ray rich afterglows. To reach this goal Pharos will need to start the high resolution observations within 30-60 seconds after the Gamma-Ray prompt emission, and will do this exploiting autonomous and automated onboard triggers from an integrated light (< 80 kg) 5-40 keV All Sky Monitor, based on the "SuperAgile" technology.

  4. A uniform metal distribution in the intergalactic medium of the Perseus cluster of galaxies.

    PubMed

    Werner, Norbert; Urban, Ondrej; Simionescu, Aurora; Allen, Steven W

    2013-10-31

    Most of the metals (elements heavier than helium) produced by stars in the member galaxies of clusters currently reside within the hot, X-ray-emitting intra-cluster gas. Observations of X-ray line emission from this intergalactic medium have suggested a relatively small cluster-to-cluster scatter outside the cluster centres and enrichment with iron out to large radii, leading to the idea that the metal enrichment occurred early in the history of the Universe. Models with early enrichment predict a uniform metal distribution at large radii in clusters, whereas those with late-time enrichment are expected to introduce significant spatial variations of the metallicity. To discriminate clearly between these competing models, it is essential to test for potential inhomogeneities by measuring the abundances out to large radii along multiple directions in clusters, which has not hitherto been done. Here we report a remarkably uniform iron abundance, as a function of radius and azimuth, that is statistically consistent with a constant value of ZFe = 0.306?±?0.012 in solar units out to the edge of the nearby Perseus cluster. This homogeneous distribution requires that most of the metal enrichment of the intergalactic medium occurred before the cluster formed, probably more than ten billion years ago, during the period of maximal star formation and black hole activity. PMID:24172976

  5. The First Science Flight of the Faint Intergalactic medium Redshifted Emission Balloon (FIREBALL)

    NASA Astrophysics Data System (ADS)

    Martin, Christopher; Milliard, Bruno; Schiminovich, David; Tuttle, Sarah; Matuszewski, Matt; Rahman, Shahin; Evrard, Jean; Frank, Stephan; Deharveng, Jean-Michel; Peroux, Celine

    We have completed the second flight of the path-finding experiment, the Faint Intergalactic medium Redshifted Emission Balloon (FIREBALL), designed to discover and map faint emis-sion from the Intergalactic Medium (IGM). The second flight was fully successful, proving a fully functional fine pointing gondola with arcsec level capability, a 1 meter diameter (fixed) parabola primary telescope with planar sidereostat for pointing, a complete closed loop guide camera and control software, and a fiber fed UV integral field spectrograph feeding a spare GALEX Near UV detector. Three scientific targets were observed, and analysis of the data shows that the instrument performed as expected. The flux measurements obtained will be compared to models for IGM emission. We discuss future modifications to the payload that will achieve a 10-to 30-fold increase in sensitivity over science flight 1. We also discuss other instrument configurations that can utilize the 1-meter UV telescope and arcsecond pointing platform, and their corresponding science objectives. FIREBALL is a collaboration of NASA, Caltech, Columbia University, CNES, and Laboratorie Astrophysique Marseille, and is sup-ported by NASA, CNES, and CNRS.

  6. On The Source of Ionization of The Intergalactic Medium at $z \\sim 2.4$

    E-print Network

    Shiv K. Sethi; Biman B. Nath

    1997-03-20

    We use the recent detection of He II absorption at $z=2.2-2.6$ in the line of sight of the quasar HS1700+64 to put bounds on the sources of ionization. We find that given the uncertainty in $\\tauhgp$ and the model of absorption in the intergalactic medium (IGM), a wide range of possible sources of ionization is still allowed by the observations. We show that a significant contribution from star forming galaxies is allowed and is consistent with the proximity effect. In the case of photoionization by the UV background radiation, the contribution of star forming galaxies to the intensity at $912 > {\\AA}$ can be within a range of $\\sim 1 - 15$ times that of the quasars. We also investigate the case of a collisionally ionized intergalactic medium. We show that although collisional ionization can be a dominant source of ionization at $z \\sim 2.4$ (taking into account the upper limit on Compton y-parameter of the microwave background radiation), the thermal state of the IGM cannot yet be determined. We also consider Sciama's model of radiatively decaying neutrinos and show that the model of decaying neutrino is consistent with the observations.

  7. Realistic Multi-ion Absorption Spectra from Simulations of the Intergalactic Medium

    NASA Astrophysics Data System (ADS)

    Kneibel, Jacob; Silvia, Devin; O'Shea, Brian W.

    2015-01-01

    Observational efforts to form a complete baryon census below a redshift of z ~ 3 have proven to be a difficult undertaking. Simulations suggest that much of this baryonic matter may exist between galaxies at low to moderate densities and temperatures of 105 to 107 K, which is best detected by absorption features in the spectra of distant quasars. Due to the challenges of detecting the warm-hot intergalactic medium (WHIM), single ion studies are insufficient in tracing the properties of the WHIM and multi-ion studies are becoming increasingly important. Using cosmological simulations of the IGM, we investigate the ionization structure using multiple ions, including commonly observed species such as OVI, CIV, and NeVIII. To examine the simulation in a manner similar to observations of the IGM, we created a pipeline for producing synthetic absorption spectra from simulated light rays that mimic spectra acquired by observations. Specifically, we add observational noise and convolve the synthetic spectrum with the line spread function of the Cosmic Origins Spectrograph. We then fit the realistic spectra using an automatic process, to determine the properties of the IGM that the light ray intersects. Using the fitted spectra and the inferred physical properties, we help interpret on-going observational studies of the intergalactic medium and aid in forming a complete baryon census.

  8. The GZK Bound in Discrete Space

    E-print Network

    N. Kersting

    2006-02-14

    The maximum distance bound for ultrahigh energy cosmic rays (UHECR) with energies above the Greisen-Zatsepin-Kuzmich cutoff $\\sim 10^{19} eV$ relaxes significantly if there is some mechanism that forces UHECR to propagate in discrete intervals, rather than continuously, through intergalactic space. In particular, intervals as small as a femtometer relax the bound for protons by an order of magnitude and potentially account for the observed excess of UHECR flux.

  9. "Marijuana has been compared to walking a foot off the ground as opposed to the intergalactic voyage produced

    E-print Network

    Squire, Larry R.

    to the intergalactic voyage produced by LSD" (source- unknown) Original LSD experience "In afternoon of 16 April, 1943 of Albert Hofmann at Sandoz) when synthesizing LSD-25) #12;2 First LSD Dosing Experiment "After 40 minutes synthesizing LSD-25) Synesthesia "The guide asked me how I felt and I responded `Good'. As I uttered the word

  10. Improved Constraints on The Neutral Intergalactic Hydrogen Surrounding Quasars at Redshifts z>6

    E-print Network

    Stuart Wyithe; Abraham Loeb; Chris Carilli

    2004-11-23

    We analyze the evolution of HII regions around the seven known SDSS quasars at z>6. The comparison between observed and model radii of the HII regions generated by these quasars individually, suggests that the surrounding intergalactic hydrogen is significantly neutral. When all constraints are combined, the existing quasar sample implies a volume averaged neutral fraction that is larger than 10% at z>6. This limited sample permits a preliminary analysis of the correlations between the quasar parameters, the sizes of their HII regions, and the associated constraints on the neutral hydrogen fraction. We find no evidence in these correlations to contradict the interpretation that the red side of the Gunn-Peterson trough corresponds to the boundary between an HII region and a partially neutral IGM.

  11. A Simple Analytic Treatment of the Intergalactic Absorption Effect in Blazar Gamma-ray Spectra

    E-print Network

    F. W. Stecker; S. T. Scully

    2006-11-13

    We derive a new and user friendly simple analytic approximation for determining the effect of intergalactic absorption in the energy range 0.2-2 TeV and the redshift range 0.05-0.4. In these ranges, the form of the absorption coeeficient is approximately logarithmic in energy. The effect of this energy dependence is to steepen intrinsic source spectra such that a source with an approximate power-law intrinsic spectrum in this energy range with spectral index $\\Gamma_{s}$ is steepened to a power-law with an observed spectral index $\\Gamma_{o} = $\\Gamma_{s} + $\\Delta \\Gamma (z)$ where $\\Delta \\Gamma (z)$ is a linear function of z in the redshift range 0.05-0.4. We apply this approximation to the spectra of seven TeV blazars.

  12. Patchy blazar heating: diversifying the thermal history of the intergalactic medium

    E-print Network

    Lamberts, Astrid; Pfrommer, Christoph; Puchwein, Ewald; Broderich, Avery E; Shalaby, Mohamad

    2015-01-01

    TeV-blazars potentially heat the intergalactic medium (IGM) as their gamma rays interact with photons of the extragalactic background light to produce electron-positron pairs, which lose their kinetic energy to the surrounding medium through plasma instabilities. This results in a heating mechanism that is only weakly sensitive to the local density, and therefore approximately spatially uniform, naturally producing an inverted temperature-density relation in underdense regions. In this paper we go beyond the approximation of uniform heating and quantify the heating rate fluctuations due to the clustered distribution of blazars and how this impacts on the thermal history of the IGM. We analytically compute a filtering function that relates the heating rate fluctuations to the underlying dark matter density field. We implement it in the cosmological code GADGET-3 and perform large scale simulations to determine the impact of inhomogeneous heating. We show that, because of blazar clustering, blazar heating is in...

  13. Measuring the equation of state of the high-z intergalactic medium using curvature statistics

    NASA Astrophysics Data System (ADS)

    Padmanabhan, Hamsa; Srianand, R.; Choudhury, T. Roy

    2015-06-01

    Using hydrodynamical simulations, we explore the use of the mean and percentiles of the curvature distribution function to recover the equation of state of the high-z (2 < z < 4) intergalactic medium (IGM). We find that the mean and percentiles of the absolute curvature distribution exhibit tight correlation with the temperatures measured at respective characteristic overdensities bar{? }_is at each redshift. Hence, they provide complementary probes of the same underlying temperature-density distribution, and can in principle be used to simultaneously recover both parameters T0 and ? of the IGM effective equation of state. We quantify the associated errors in the recovered parameters T0 and ? from the intrinsic scatter in the characteristic overdensities and the uncertainties in the curvature measurement.

  14. Probing the Intergalactic Magnetic Field with the Anisotropy of the Extragalactic Gamma-ray Background

    NASA Technical Reports Server (NTRS)

    Venters, T. M.; Pavlidou, V.

    2013-01-01

    The intergalactic magnetic field (IGMF) may leave an imprint on the angular anisotropy of the extragalactic gamma-ray background through its effect on electromagnetic cascades triggered by interactions between very high energy photons and the extragalactic background light. A strong IGMF will deflect secondary particles produced in these cascades and will thus tend to isotropize lower energy cascade photons, thereby inducing a modulation in the anisotropy energy spectrum of the gamma-ray background. Here we present a simple, proof-of-concept calculation of the magnitude of this effect and demonstrate that current Fermi data already seem to prefer nonnegligible IGMF values. The anisotropy energy spectrum of the Fermi gamma-ray background could thus be used as a probe of the IGMF strength.

  15. A census of H? emitters in the intergalactic medium of the NGC 2865 system

    NASA Astrophysics Data System (ADS)

    Urrutia-Viscarra, F.; Arnaboldi, M.; Mendes de Oliveira, C.; Gerhard, O.; Torres-Flores, S.; Carrasco, E. R.; de Mello, D.

    2014-09-01

    Tidal debris, which are rich in HI gas and formed in interacting and merging systems, are suitable laboratories to study star formation outside galaxies. Recently, several such systems were observed, which contained many young star forming regions outside the galaxies. In previous works, we have studied young star forming regions outside galaxies in different systems with optical and/or gaseous tidal debris, in order to understand how often they occur and in which type of environments. In this paper, we searched for star forming regions around the galaxy NGC 2865, a shell galaxy that is circled by a ring of HI with a total mass of 1.2 × 109 M?. Using the multi-slit imaging spectroscopy technique with the Gemini telescope, we detected all H? emitting sources in the surroundings of the galaxy NGC 2865, down to a flux limit of 10-18 erg cm-2 s-1 Å-1. With the spectra information and the near and far-ultraviolet flux, we characterize the star formation rates, masses, ages, and metallicities for these HII regions. In total, we found 26 emission-line sources in a 60 × 60 Kpc field centered over the southeastern tail of the HI gas present around the galaxy NGC 2865. Out of the 26 H? emitters, 19 are in the satellite galaxy FGCE 0745, and seven are intergalactic HII regions scattered over the south tail of the HI gas around NGC 2865. We found that the intergalactic HII regions are young (<200 Myr) with stellar masses in the range 4 × 103 M? to 17 × 106 M?. These are found in a region of low HI gas density, where the probability of forming stars is expected to be low. For one of the intergalactic HII regions, we estimated a solar oxygen abundance of 12 + log(O/H) ~ 8.7. We also were able to estimate the metallicity for the satellite galaxy FGCE 0745 to be 12 + log(O/H) ~ 8.0. Given these physical parameters, the intergalactic HII regions are consistent with young star forming regions (or clusters), which are born in situ outside the NGC 2865 galaxy from a pre-enriched gas removed from the host galaxies in a merger event. The relevance of these observations is discussed. Based on observations obtained at the Gemini Observatory, which is operated by the Association of Universities for Research in Astronomy, Inc., under a cooperative agreement with the NSF on behalf of the Gemini partnership: the National Science Foundation (United States), the Science and Technology Facilities Council (United Kingdom), the National Research Council (Canada), CONICYT (Chile), the Australian Research Council (Australia), Ministério da Ciência e Tecnologia (Brazil) and Ministerio de Ciencia, Tecnología e Innovación Productiva (Argentina) - Observing runs: GS-2008A-Q-35.

  16. Evolution of Structure in the Intergalactic Medium and the Nature of the Ly-alpha Forest

    E-print Network

    HongGuang Bi; Arthur F. Davidsen

    1996-11-11

    We have performed a detailed statistical study of the evolution of structure in a photoionized intergalactic medium (IGM) using analytical simulations to extend the calculation into the mildly non-linear density regime found to prevail at z = 3. Our work is based on a simple fundamental conjecture: that the probability distribution function of the density of baryonic diffuse matter in the universe is described by a lognormal (LN) random field. The LN field has several attractive features and follows plausibly from the assumption of initial linear Gaussian density and velocity fluctuations at arbitrarily early times. Starting with a suitably normalized power spectrum of primordial fluc- tuations in a universe dominated by cold dark matter (CDM), we compute the behavior of the baryonic matter, which moves slowly toward minima in the dark matter potential on scales larger than the Jeans length. We have computed two models that succeed in matching observations. One is a non-standard CDM model with Omega=1, h=0.5 and \\Gamma=0.3, and the other is a low density flat model with a cosmological constant(LCDM), with Omega=0.4, Omega_Lambda=0.6 and h=.65. In both models, the variance of the density distribution function grows with time, reaching unity at about z=4, where the simulation yields spectra that closely resemble the Ly-alpha forest absorption seen in the spectra of high z quasars. The calculations also successfully predict the observed properties of the Ly-alpha forest clouds and their evolution from z=4 down to at least z=2, assuming a constant intensity for the metagalactic UV background over this redshift range. However, in our model the forest is not due to discrete clouds, but rather to fluctuations in a continuous intergalactic medium. (This is an abreviated abstract; the complete abstract is included with the manuscript.)

  17. Small Scale Structure at High Redshift: III. The Clumpiness of the Intergalactic Medium on Sub-kpc Scales

    Microsoft Academic Search

    Michael Rauch; Wallace L. W. Sargent; Thomas A. Barlow; Robert F. Carswell

    2001-01-01

    Spectra from the Keck HIRES instrument of the Lyman alpha forests in the\\u000alines of sight to the A and C components of the gravitationally lensed QSO\\u000aQ1422+231 were used to investigate the structure of the intergalactic medium at\\u000amean redshift z = 3.3 on sub-kpc scales. We measured the cross-correlation\\u000aamplitude between the two Lyman alpha forests for a

  18. DETECTING THE WARM-HOT INTERGALACTIC MEDIUM THROUGH X-RAY ABSORPTION LINES

    SciTech Connect

    Yao Yangsen; Shull, J. Michael; Cash, Webster [Center for Astrophysics and Space Astronomy, Department of Astrophysical and Planetary Sciences, University of Colorado, 389 UCB, Boulder, CO 80309 (United States); Wang, Q. Daniel, E-mail: yaoys@colorado.edu [Department of Astronomy, University of Massachusetts, Amherst, MA 01003 (United States)

    2012-02-20

    The warm-hot intergalactic medium (WHIM) at temperatures 10{sup 5}-10{sup 7} K is believed to contain 30%-50% of the baryons in the local universe. However, all current X-ray detections of the WHIM at redshifts z > 0 are of low statistical significance ({approx}< 3{sigma}) and/or controversial. In this work, we aim to establish the detection limits of current X-ray observatories and explore requirements for next-generation X-ray telescopes for studying the WHIM through X-ray absorption lines. We analyze all available grating observations of Mrk 421 and obtain spectra with signal-to-noise ratios (S/Ns) of {approx}90 and 190 per 50 mA spectral bin from Chandra and XMM-Newton observations, respectively. Although these spectra are two of the best ever collected with Chandra and XMM-Newton, we cannot confirm the two WHIM systems reported by Nicastro et al. in 2005. Our bootstrap simulations indicate that spectra with such high S/N cannot constrain the WHIM with O VII column densities N{sub Ovii}{approx}10{sup 15} cm{sup -2} (corresponding to an equivalent width of 2.5 mA for a Doppler velocity of 50 km s{sup -1}) at {approx}> 3{sigma} significance level. The simulation results also suggest that it would take >60 Ms for Chandra and 140 Ms for XMM-Newton to measure the N{sub Ovii} at {>=}4{sigma} from a spectrum of a background QSO with flux of {approx}0.2 mCrab (1 Crab = 2 Multiplication-Sign 10{sup -8} erg s{sup -1} cm{sup -2} at 0.5-2 keV). Future X-ray spectrographs need to be equipped with spectral resolution R {approx} 4000 and effective area A {>=} 100 cm{sup 2} to accomplish the similar constraints with an exposure time of {approx}2 Ms and would require {approx}11 Ms to survey the 15 QSOs with flux {approx}> 0.2 mCrab along which clear intergalactic O VI absorbers have been detected.

  19. Heating and ionization of the primordial intergalactic medium by high-mass X-ray binaries

    NASA Astrophysics Data System (ADS)

    Knevitt, G.; Wynn, G. A.; Power, C.; Bolton, J. S.

    2014-12-01

    We investigate the influence of high-mass X-ray binaries (HMXBs) on their high-redshift environments. Using a one-dimensional radiative transfer code, we predict the ionization and temperature profiles surrounding a coeval stellar population, composed of main-sequence stars and HMXBs, at various times after its formation. We consider both uniform density surroundings, and a cluster embedded in a 108 M? Navarro-Frenk-White (NFW) halo. HMXBs in a constant density environment produce negligible enhanced ionization because of their high-energy spectral energy distributions and short lifetimes. In this case, HMXBs only marginally contribute to the local heating rate. For NFW profiles, radiation from main-sequence stars cannot prevent the initially ionized volume from recombining since it is unable to penetrate the high-density galactic core. However, HMXB photons stall recombinations behind the front, keeping it partially ionized for longer. The increased electron density in these partially ionized regions promotes further cooling, resulting in lower intergalactic medium (IGM) temperatures. In the context of this starburst model, we have shown that HMXBs do not make a major contribution to reionization or IGM heating. However, X-ray escape fractions are high in both density profile cases. Continuous star formation may result in the build up of X-rays over time, reducing the ionization time-scale and potentially leading to low level ionization of the distant IGM.

  20. Cosmic Variance In the Transparency of the Intergalactic Medium After Reionization

    E-print Network

    Stuart Wyithe; Abraham Loeb

    2006-01-30

    Following the completion of cosmic reionization, the mean-free-path of ionizing photons was set by a population of Ly-limit absorbers. As the mean-free-path steadily grew, the intensity of the ionizing background also grew, thus lowering the residual neutral fraction of hydrogen in ionization equilibrium throughout the diffuse intergalactic medium (IGM). Ly-alpha photons provide a sensitive probe for tracing the distribution of this residual hydrogen at the end of reionization. Here we calculate the cosmic variance among different lines-of-sight in the distribution of the mean Ly-alpha optical depths. We find fractional variations in the effective post-reionization optical depth that are of order unity on a scale of ~100 co-moving Mpc, in agreement with observations towards high-redshift quasars. Significant contributions to these variations are provided by the cosmic variance in the density contrast on the scale of the mean-free-path for ionizing photons, and by fluctuations in the ionizing background induced by delayed or enhanced structure formation. Cosmic variance results in a highly asymmetric distribution of transmission through the IGM, with fractional fluctuations in Ly-alpha transmission that ar larger than in Ly-beta transmission.

  1. The Scattering of Lyman-series Photons in the Intergalactic Medium

    E-print Network

    Steven Furlanetto; Jonathan R. Pritchard

    2006-05-26

    We re-examine scattering of photons near the Lyman-alpha resonance in the intergalactic medium (IGM). We first derive a general integral solution for the radiation field around resonance when spin diffusivity is ignored. Our solution shows explicitly that recoil sources an absorption feature, whose magnitude increases with the relative importance of recoil compared to Doppler broadening. This spectrum depends on the Lyman-alpha line profile, but approximating it with the absorption profile appropriate to the Lorentzian wings of natural broadening accurately reproduces the results for a full Voigt profile so long as T<1000 K in the IGM. This approximation allows us to obtain simple analytic formulae for the total scattering rate of Lyman-alpha photons and the accompanying energy exchange rate. Our power series solutions converge rapidly for photons that redshift into the Lyman-alpha resonance as well as for photons injected at line center. We confirm previous calculations showing that heating through this mechanism is quite slow and probably negligible compared to other sources. We then show that energy exchange during the scattering of higher-order Lyman-series photons can be much more important than naively predicted by recoil arguments. However, the resulting heating is still completely negligible.

  2. Search for Oxygen Emission from Warm-Hot Intergalactic Medium around A2218 with Suzaku

    SciTech Connect

    Takei, Yoh; Ohashi, Takaya; Henry, J.Patrick; Mitsuda, Kazuhisa; Fujimoto, Ryuichi; Tamura, Takayuki; Yamasaki, Noriko Y.; Hayashida, Kiyoshi; Tawa, Noriaki; Matsushita,; Bautz, Mark W.; Hughes, John P.; Madejski, Grzegorz M.; Kelley, Richard L.; Arnaud, Keith A.; /JAXA, Sagamihara /Tokyo Metropolitan U. /Inst. Astron., Honolulu /Osaka U.

    2006-09-08

    We searched for redshifted O emission lines from the possible warm-hot intergalactic medium (WHIM) surrounding the cluster of galaxies A2218 at z = 0.1756 using the XIS instrument on Suzaku. This cluster is thought to have an elongated structure along the line of sight based on previous studies. We studied systematic uncertainties in the spectrum of the Galactic emission and in the soft X-ray response of the detectors due to the contamination building up on the XIS filters. We detected no significant redshifted O lines, and set a tight constraint on the intensity with upper limits for the surface brightness of O{sub VII} and O{sub VIII} lines of 1.1 x 10{sup -7} and 3.0 x 10{sup -7} photons cm{sup -2} s{sup -1} arcmin{sup -2}, respectively. These upper limits are significantly lower than the previously reported fluxes from the WHIM around other clusters of galaxies. We also discuss the prospect for the detection of the WHIM lines with Suzaku XIS in the future.

  3. Pharos: A High Resolution Intergalactic Explorer for the Soft X-ray

    NASA Astrophysics Data System (ADS)

    Elvis, M.; Fiore, F.; Pharos Collaboration

    2003-12-01

    We present a mission concept for high resolution X-ray spectroscopy with a resolving power, R > 6000 at ? > 21 Å, (c.f. R < 1000 for Chandra and XMM-Newton). Such a mission could be small and have a rapid response allowing us to `X-ray the Universe' using the afterglows of Gamma-ray Bursts (GRBs) and the prompt of ``X-ray Rich Bursts, in addition to quasars, to illuminate the `Cosmic Web', which is predicted to contain most of the baryons in the nearby Universe. The combination of moderate effective area below E ˜ 0.9 keV (A ˜ 1000-2000 cm2) and high spectral resolution (? v < 50 km/s at ? 21 Å) will allow us to search for faint metal absorption lines in the intervening Warm-Hot Intergalactic Medium (WHIM) as well as the GRB host galaxy Inter-Stellar Matter (ISM), and to resolve internal gas and galaxy motions within larger structures. This would provide probes of the metal enrichment and heating histories of both the WHIM and the high redshift ISM. M.E. acknowledges support by the NASA contract NAS8-39073 (CXC)

  4. Enrichment of the Intergalactic Medium by Radiation Pressure Driven Dust Efflux

    E-print Network

    Anthony Aguirre; Lars Hernquist; Neal Katz; Jeffrey Gardner; David Weinberg

    2001-06-08

    The presence of metals in hot cluster gas and in Ly-alpha absorbers, as well as the mass-metallicity relation of observed galaxies, suggest that galaxies lose a significant fraction of their metals to the intergalactic medium (IGM). Theoretical studies of this process have concentrated on metal removal by dynamical processes or supernova-driven winds. Here, we investigate the enrichment of the IGM by the expulsion of dust grains from galaxies by radiation pressure. We use already completed cosmological simulations, to which we add dust assuming that most dust can reach the equilibrium point between radiation pressure and gravitational forces. We find that the expulsion of dust and its subsequent (partial) destruction in the IGM can plausibly account for the observed level of C and Si enrichment of the z=3 IGM. At low-z, dust ejection and destruction could explain a substantial fraction of the metals in clusters, but it cannot account for all of the chemical species observed. Dust expelled by radiation pressure could give clusters a visual opacity of up to 0.2-0.5 mag in their central regions even after destruction by the hot intracluster medium; this value is interestingly close to limits and claimed observations of cluster extinction. We also comment on the implications of our results for the opacity of the general IGM. Finally, we suggest a possible `hybrid' scenario in which winds expel gas and dust into galaxy halos but radiation pressure distributes the dust uniformly through the IGM.

  5. Intergalactic Magnetic Field and Arrival Direction of Ultra-High-Energy Iron Nuclei

    NASA Astrophysics Data System (ADS)

    Kang, Hyesung; Das, S.; Ryu, D.

    2012-05-01

    We have studied how the intergalactic magnetic field (IGMF) affects the propagation of super-GZK iron nuclei that originate from extragalactic sources within the local GZK sphere. Toward this end, we set up hypothetical sources of ultra-high-energy cosmic-rays (UHECRs), virtual observers, and the magnetized cosmic web in a model universe constructed from cosmological structure formation simulations. We then arranged a set of reference objects at high density region to represent astronomical objects formed in the large scale structure (LSS).With our model IGMF, the paths of UHE iron nuclei are deflected on average by about 70 degrees, which might indicate a nearly isotropic distribution of arrival directions. However, the separation angle between the arrival directions and the nearest reference object on the LSS is only 6 degrees, which is twice the mean distance to the nearest neighbors among the reference objects. This means that the positional correlation of observed UHE iron events with their true sources would be erased by the IGMF, but the correlation with the LSS itself is to be sustained. We discuss implications of our findings for correlations studies of real UHECR events.This research was supported by Basic Science Research Program through the National Research Foundation of Korea (NRF) funded by the Ministry of Education, Science and Technology (2011-0002433).

  6. THE SIGNATURE OF THE WARM-HOT INTERGALACTIC MEDIUM IN WMAP AND THE FORTHCOMING PLANCK DATA

    SciTech Connect

    Suarez-Velasquez, I.; Kitaura, F.-S.; Muecket, J. P. [Leibniz-Institut fuer Astrophysik, D-14482 Potsdam (Germany); Atrio-Barandela, F., E-mail: isuarez@aip.de, E-mail: kitaura@aip.de, E-mail: jpmuecket@aip.de, E-mail: atrio@usal.es [Fisica Teorica, Universidad de Salamanca, E-37008 Salamanca (Spain)

    2013-05-20

    We compute the cross-correlation between the Warm-Hot Intergalactic Medium and maps of cosmic microwave background temperature anisotropies using a log-normal probability density function to describe the weakly nonlinear matter density field. We search for this contribution in the data measured by the Wilkinson Microwave Anisotropy Probe. We use a template of projected matter density reconstructed from the Two-Micron All-Sky Redshift Survey as a tracer of the electron distribution. The spatial distribution of filaments is modeled using the recently developed Augmented Lagrangian Perturbation Theory. On the scales considered here, the reconstructed density field is very well described by the assumed log-normal distribution function. We predict that the cross-correlation will have an amplitude of 0.03-0.3 {mu}K. The measured value is close to 1.5 {mu}K, compatible with random alignments between structure in the template and in the temperature anisotropy data. Using the W1 Differencing Assembly to remove this systematic gives a residual correlation dominated by Galactic foregrounds. Planck could detect the Warm-Hot Medium if it is well traced by the density field reconstructed from galaxy surveys. The 217 GHz channel will allow to eliminate spurious contributions and its large frequency coverage can show the sign change from the Rayleigh-Jeans to the Wien part of the spectrum, characteristic of the thermal Sunyaev-Zel'dovich effect.

  7. Strength of the spontaneously emitted collective aperiodic magnetic field fluctuations in the reionized early intergalactic medium

    SciTech Connect

    Schlickeiser, R.; Felten, T., E-mail: rsch@tp4.rub.de, E-mail: tim.felten@rub.de [Institut für Theoretische Physik, Lehrstuhl IV: Weltraum- und Astrophysik, Ruhr-Universität Bochum, D-44780 Bochum (Germany)

    2013-11-20

    Nonmagnetized, fully ionized plasmas spontaneously emit aperiodic turbulent magnetic field fluctuations. Its fluctuation intensities are dominated by the contribution from a recently discovered collective, damped mode, which modifies the earlier estimate of the total magnetic field strength in a thermal nonrelativistic electron-proton plasma to |?B|=24?{sub e}{sup 1/4}(gn{sub e}m{sub e}c{sup 2}){sup 1/2} G, where g denotes the plasma parameter and ? {sub e} the thermal electron velocity in units of the speed of light, in the case of no collisional damping. Accounting for simultaneous viscous damping reduces the estimate to |?B|{sub eq} = 2305g(n{sub e}m{sub e}c {sup 2}){sup 1/2} G, depending only on the plasma parameter g and the electron density n{sub e} . For the unmagnetized intergalactic medium, immediately after the reionization onset the field strengths from this mechanism are about 6.8 × 10{sup –13} G for no collisional damping and 1.5 × 10{sup –16} G for viscous damping. Maximum spatial scales of 10{sup 15} cm of the emitted aperiodic fluctuations in cosmic voids are possible.

  8. Heating and Ionization of the Intergalactic Medium by an Early X-Ray Background

    E-print Network

    Aparna Venkatesan; Mark L. Giroux; J. Michael Shull

    2001-08-09

    Observational studies indicate that the intergalactic medium (IGM) is highly ionized up to redshifts just over 6. A number of models have been developed to describe the process of reionization and the effects of the ionizing photons from the first luminous objects. In this paper, we study the impact of an X-ray background, such as high-energy photons from early quasars, on the temperature and ionization of the IGM prior to reionization, before the fully ionized bubbles associated with individual sources have overlapped. X-rays, which have large mean free paths relative to EUV photons, and their photoelectrons can have significant effects on the thermal and ionization balance. We find that hydrogen ionization is dominated by the X-ray photoionization of neutral helium and the resulting secondary electrons. Thus, the IGM may have been warm and weakly ionized prior to full reionization. We examine several related consequences, including the filtering of the baryonic Jeans mass scale, signatures in the cosmic microwave background, and the H$^{-}$-catalyzed production of molecular hydrogen.

  9. Cosmic gamma-ray background from structure formation in the intergalactic medium

    PubMed

    Loeb; Waxman

    2000-05-11

    The Universe is filled with a diffuse background of gamma-ray radiation, the origin of which remains one of the unsolved puzzles of cosmology. Less than one-quarter of the gamma-ray flux can be attributed to unresolved discrete sources, such as active galactic nuclei; the remainder appears to constitute a truly diffuse background. Here we show that the shock waves induced by gravity in the gas of the intergalactic medium, during the formation of large-scale structures like filaments and sheets of galaxies, produce a population of highly relativistic electrons. These electrons scatter a small fraction of the cosmic microwave background photons in the local Universe up to gamma-ray energies, thereby providing the gamma-ray background. The predicted diffuse flux agrees with the observed background across more than four orders of magnitude in photon energy, and the model predicts that the gamma-ray background, though generated locally, is isotropic to better than five per cent on angular scales larger than a degree. Moreover, the agreement between the predicted and observed background fluxes implies a mean cosmological density of baryons that is consistent with Big Bang nucleosynthesis. PMID:10821264

  10. The evolving intergalactic medium - The uncollapsed baryon fraction in a cold dark matter universe

    NASA Technical Reports Server (NTRS)

    Shapiro, Paul R.; Giroux, Mark L.; Babul, Arif

    1991-01-01

    The time-varying density of the intergalactic medium (IGM) is calculated by coupling detailed numerical calculations of the thermal and ionization balance and radiative transfer in a uniform IGM of H and He to the linearized equations for the growth of density fluctuations in both gases and a dark component in a cold dark matter universe. The IGM density is identified with the collapsed baryon fraction. It is found that even if the IGM is never reheated, a significant fraction of the baryons remain uncollapsed at redshifts of four. If instead the collapsed fraction releases enough ionizing radiation or thermal energy to reionize the IGM by z greater than four as required by the Gunn-Peterson (GP) constraint, the uncollapsed fraction at z of four is even higher. The known quasar distribution is insufficient to supply the ionizing radiation necessary to satisfy the GP constraint in this case and, if stars are instead responsible, a substantial metallicity must have been produced by z of four.

  11. Astrophysical bow shocks: An analytical solution for the hypersonic blunt body problem in the intergalactic medium

    E-print Network

    Schulreich, Michael Mathias

    2011-01-01

    Aims: Bow shock waves are a common feature of groups and clusters of galaxies since they are generated as a result of supersonic motion of galaxies through the intergalactic medium. The goal of this work is to present an analytical solution technique for such astrophysical hypersonic blunt body problems. Methods: A method, developed by Schneider (1968, JFM, 31, 397) in the context of aeronautics, allows calculation of the galaxy's shape as long as the shape of the bow shock wave is known (so-called inverse method). In contrast to other analytical models, the solution is valid in the whole flow region (from the stagnation point up to the bow shock wings) and in particular takes into account velocity gradients along the streamlines. We compare our analytical results with two-dimensional hydrodynamical simulations carried out with an extended version of the VH-1 hydrocode which is based on the piecewise parabolic method with a Lagrangian remap. Results: It is shown that the applied method accurately predicts the...

  12. Morphology of blazar-induced gamma ray halos due to a helical intergalactic magnetic field

    E-print Network

    Long, Andrew J

    2015-01-01

    We study the characteristic size and shape of idealized blazar-induced cascade halos in the $1-100 \\, {\\rm GeV}$ energy range assuming various non-helical and helical configurations for the intergalactic magnetic field (IGMF). While the magnetic field creates an extended halo, the helicity provides the halo with a twist. Under simplifying assumptions, we assess the parameter regimes for which it is possible to measure the size and shape of the halo from a single source and then to deduce properties of the IGMF. We find that blazar halo measurements with an experiment similar to Fermi-LAT are best suited to probe a helical magnetic field with strength and coherence length today in the ranges $10^{-17} \\lesssim B_{0} / {\\rm Gauss} \\lesssim 10^{-13}$ and $10 \\, {\\rm Mpc} \\lesssim \\lambda \\lesssim 10 \\, {\\rm Gpc}$ where $\\mathcal{H} \\sim B_0^2 / \\lambda$ is the magnetic helicity density. Stronger magnetic fields or smaller coherence scales can still potentially be investigated, but the connection between the halo...

  13. The Hot Inter-Galactic Medium and the Cosmic Microwave Background

    E-print Network

    Michael Fisher

    2007-05-01

    The physical characteristics of the Lyman-alpha forest cloud systems are combined with observations on the baryonic mass density of the Universe and constraints from primordial nucleosynthesis to set boundary conditions on the Intergalactic Medium (IGM) at the epoch of z=2.5. The Universe is considered a closed system and allowed to expand adiabatically from the epoch when QSOs first ionized the IGM (5 <= z_on <= 20). The average kinetic energy of a gas is calculated in the region where the gas transitions from relativistic to non-relativistic behavior. All of the above measurements are then used to determine the thermal history of the IGM in the redshift range 2.5 <= z <= z_on. The hot IGM is assumed to inverse Compton scatter photons from the Cosmic Microwave Background (CMBR) and consequently distort the CMBR as seen at the present epoch. The temperature of the IGM at z=2.5 and the epoch z_on are adjusted, within the constraints defined above, to give the best overall agreement with published data on the temperature of the IGM. We find that the model of the IGM proposed here does not grossly distort the CMBR, and in fact agrees quite closely with the preliminary results from the Cosmic Background Explorer (COBE) satellite. However, our model of the IGM cannot explain the observed cosmic x ray background. This paper was originally written in 1990. It was never submitted for publication.

  14. Far Ultraviolet Spectroscopy of the Intergalactic and Interstellar Absorption Toward 3C 273

    NASA Technical Reports Server (NTRS)

    Sembach, Kenneth R.; Howk, J. Christopher; Savage, Blair D.; Shull, J. Michael; Oegerle, William R.; Fisher, Richard R. (Technical Monitor)

    2001-01-01

    We present Far Ultraviolet Spectroscopic Explorer observations of the molecular, neutral atomic, weakly ionized, and highly ionized components of the interstellar and intergalactic material toward the quasar 3C273. We identify Ly-beta absorption in eight of the known intergalactic Ly-alpha absorbers along the sight line with the rest-frame equivalent widths W(sub r)(Ly-alpha) > 50 micro-angstroms. Refined estimates of the H(I) column densities and Doppler parameters (b) of the clouds are presented. We find a range of b = 16-46 km/s. We detect multiple H(I) lines (Ly-beta - Ly-theta) in the 1590 km/s Virgo absorber and estimate logN(H(I)) = 15.85 +/- 0.10, ten times more H(I) than all of the other absorbers along the sight line combined. The Doppler width of this absorber, b = 16 km/s, implies T < 15,000 K. We detect O(VI) absorption at 1015 km/s at the 2-3(sigma) level that may be associated with hot, X-ray emitting gas in the Virgo Cluster. We detect weak C(III) and O(VI) absorption in the IGM at z=0.12007; this absorber is predominantly ionized and has N(H+)/N(H(I)) > 4000/Z, where Z is the metallicity. Strong Galactic interstellar O(VI) is present between -100 and +100 km/s with an additional high-velocity wing containing about 13% of the total O(VI) between +100 and +240 km/s. The Galactic O(VI), N(V), and C(IV) lines have similar shapes, with roughly constant ratios across the -100 to +100 km/s velocity range. The high velocity O(VI) wing is not detected in other species. Much of the interstellar high ion absorption probably occurs within a highly fragmented medium within the Loop IV remnant or in the outer cavity walls of the remnant. Multiple hot gas production mechanisms are required. The broad O(VI) absorption wing likely traces the expulsion of hot gas out of the Galactic disk into the halo. A flux limit of 5.4 x 10(epx -16) erg/sq cm/s on the amount of diffuse O(VI) emission present = 3.5' off the 3C273 sight line combined with the observed O(VI) column density toward 3C273, logN O(VI) = 14.73 +/- 0.04, implies n(sub e) < 0.02/cubic cm and P/k < 11,500/cubic cm for an assumed temperature of 3 x 10(exp 5) K. The elemental abundances in the neutral and weakly-ionized interstellar clouds are similar to those found for other halo clouds. The warm neutral and warm ionized clouds along the sight line have similar dust-phase abundances, implying that the properties of the dust grains in the two types of clouds are similar. Interstellar H2 absorption is present at positive velocities at a level of logN(H2) = 15.71, but is very weak at the velocities of the main column density concentration along the sight line observed in H(I) 21 cm emission.

  15. STAR FORMATION FEEDBACK AND METAL-ENRICHMENT HISTORY OF THE INTERGALACTIC MEDIUM

    SciTech Connect

    Cen Renyue; Chisari, Nora Elisa, E-mail: cen@astro.princeton.edu, E-mail: nchisari@astro.princeton.edu [Princeton University Observatory, Princeton, NJ 08544 (United States)

    2011-04-10

    Using the state-of-the-art cosmological hydrodynamic simulations of the standard cold dark matter model with star formation feedback strength normalized to match the observed star formation history of the universe at z= 0-6, we compute the metal-enrichment history of the intergalactic medium (IGM). Overall we show that galactic superwind (GSW) feedback from star formation can transport metals to the IGM and that the properties of simulated metal absorbers match current observations. The distance of influence of GSW from galaxies is typically limited to about {<=}0.5 Mpc and within regions of overdensity {delta} {>=} 10. Most C IV and O VI absorbers are located within shocked regions of elevated temperature (T {>=} 2 x 10{sup 4} K), overdensity ({delta} {>=} 10), and metallicity ([Z/Z{sub sun}] = [ - 2.5, - 0.5]), enclosed by double shocks propagating outward. O VI absorbers have typically higher metallicity, lower density, and higher temperature than C IV absorbers. For O VI absorbers, collisional ionization dominates over the entire redshift range z= 0-6, whereas for C IV absorbers the transition occurs at moderate redshift z {approx} 3 from collisionally dominated to photoionization dominated. We find that the observed column density distributions for C IV and O VI in the range log N cm{sup 2}=12-15 are reasonably reproduced by the simulations. The evolution of mass densities contained in C IV and O VI lines, {Omega}{sub CIV} and {Omega}{sub OVI}, is also in good agreement with observations, which shows a near constancy at low redshifts and an exponential drop beyond redshift z= 3-4. For both C IV and O VI, most absorbers are transient and the amount of metals probed by C IV and O VI lines of column log N cm{sup 2}=12-15 is only {approx}2% of total metal density at any epoch. While gravitational shocks from large-scale structure formation dominate the energy budget (80%-90%) for turning about 50% of the IGM to the warm-hot intergalactic medium (WHIM) by z = 0, GSW feedback shocks are energetically dominant over gravitational shocks at z{>=}1-2. Most of the so-called missing metals at z= 2-3 are hidden in a warm-hot (T = 10{sup 4.5}-10{sup 7} K) gaseous phase, heated up by GSW feedback shocks. Their mass distribution is broadly peaked at {delta}=1-10 in the IGM, outside virialized halos. Approximately 37%, 46%, 10%, and 7% of the total metals at z = 0 are in stars, WHIM, X-ray gas, and cold gas, respectively; the distributions stand at 23%, 57%, 2%, and 18% and 14%, 51%, 4%, and 31% at z = 2 and z = 4, respectively.

  16. Constraining the Baryon Fraction in the Warm Hot Intergalactic Medium at Low Redshifts with Planck Data

    NASA Astrophysics Data System (ADS)

    Génova-Santos, R.; Atrio-Barandela, F.; Kitaura, F.-S.; Mücket, J. P.

    2015-06-01

    We cross-correlate foreground cleaned Planck Nominal cosmic microwave background (CMB) maps with two templates constructed from the Two-Micron All-Sky Redshift Survey of galaxies. The first template traces the large-scale filamentary distribution characteristic of the Warm–Hot Intergalactic Medium (WHIM) out to ? 90 {{h}-1} Mpc. The second preferentially traces the virialized gas in unresolved halos around galaxies. We find a marginal signal from the correlation of Planck data and the WHIM template with a signal to noise from 0.84 to 1.39 at the different Planck frequencies, and with a frequency dependence compatible with the thermal Sunyaev–Zel’dovich effect. When we restrict our analysis to the 60% of the sky outside the plane of the Galaxy and known point sources and galaxy clusters, the cross-correlation at zero lag is 0.064+/- 0.051 ? K. The correlation extends out to ? 6{}^\\circ , which at the median depth of our template corresponds to a physical length of ? 6--8 {{h}-1} Mpc. On the same fraction of the sky, the cross-correlation of the CMB data with the second template is \\lt 0.17 ? K (95% C.L.), providing no statistically significant evidence of a contribution from bound gas to the previous result. This limit translates into a physical constraint on the properties of the shock-heated WHIM of a log-normal model describing the weakly nonlinear density field. We find that our upper limit is compatible with a fraction of 45% of all baryons residing in filaments at overdensities ?1–100 and with temperatures in the range {{10}4.5}--{{10}7.5} K, in agreement with the detection at redshift z? 0.5 of Van Waerbeke et al..

  17. Unlocking the secrets of absorption line complexes in the intergalactic medium

    NASA Astrophysics Data System (ADS)

    O'Shea, Brian

    2013-10-01

    It is well-established that the fraction of baryons in the Universe that are observable drops from nearly 100% at z 3 to less than 50% by z 0. Simulations predict that most of the missing baryons are located in the IGM at moderate densities and at temperatures of 10^5-10^7 K - gas that is generally in the filaments of the cosmic web and in circumgalactic regions. This gas is typically detected in the low-z Lyman alpha forest by measuring UV absorption lines of highly ionized metals, such as CIV and OVI. However, significant uncertainties exist relating to the physical conditions of the gas associated with these lines {such as temperature, metallicity, and ionization state}, which severely limits our ability to understand the physical environment of these absorbers. We propose to clarify the relationship between the multi-species absorption line complexes seen in QSO spectra and the physical conditions of the corresponding absorbing gas. We will do this using synthetic observing tools and the largest, most detailed simulations of the IGM to date, which include a new sophisticated treatment of non-equilibrium gas chemistry. We will create catalogs that enable conversion between specific combinations of observed absorption lines and the equivalent physical gas distribition, will calculate the total baryon content that is traceable with each ion, and will devise tests to distinguish between the circumgalactic and truly intergalactic medium. This work will be critical to the interpretation of previous and ongoing HST studies of the IGM - particularly those using the Cosmic Origins Spectrograph - and directly addresses the HST Cycle 21 Ultraviolet Initiative.

  18. COSMOLOGICAL SIMULATIONS OF INTERGALACTIC MEDIUM EVOLUTION. I. TEST OF THE SUBGRID CHEMICAL ENRICHMENT MODEL

    SciTech Connect

    Côté, Benoit; Martel, Hugo; Drissen, Laurent [Département de physique, de Génie Physique et d'Optique, Université Laval, Québec, QC G1V 0A6 (Canada)

    2013-11-10

    We present a one-zone galactic chemical enrichment model that takes into account the contribution of stellar winds from massive stars under the effect of rotation, Type II supernovae, hypernovae, stellar winds from low- and intermediate-mass stars, and Type Ia supernovae. This enrichment model will be implemented in a galactic model designed to be used as a subgrid treatment for galaxy evolution and outflow generation in large-scale cosmological simulations, in order to study the evolution of the intergalactic medium. We test our enrichment prescription by comparing its predictions with the metallicity distribution function and the abundance patterns of 14 chemical elements observed in the Milky Way stars. To do so, we combine the effect of many stellar populations created from the star formation history of the Galaxy in the solar neighborhood. For each stellar population, we keep track of its specific mass, initial metallicity, and age. We follow the time evolution of every population in order to respect the time delay between the various stellar phases. Our model is able to reproduce the observed abundances of C, O, Na, Mg, Al, S, and Ca. For Si, Cr, Mn, Ni, Cu, and Zn, the fits are still reasonable, but improvements are needed. We marginally reproduce the nitrogen abundance in very low metallicity stars. Overall, our results are consistent with the predicted abundance ratios seen in previous studies of the enrichment history of the Milky Way. We have demonstrated that our semi-analytic one-zone model, which cannot deal with spatial information such as the metallicity gradient, can nevertheless successfully reproduce the global Galactic enrichment evolution obtained by more complex models, at a fraction of the computational cost. This model is therefore suitable for a subgrid treatment of chemical enrichment in large-scale cosmological simulations.

  19. X-Ray Constraints on the Warm-Hot Intergalactic Medium

    NASA Technical Reports Server (NTRS)

    Kuntz, K. D.; Snowden, S. I.; Mushotzky, R. F.; White, Nicholas E. (Technical Monitor)

    2000-01-01

    Three observational constraints can be placed on a warm-hot intergalactic medium (WHIM) using ROSAT Position Sensitive Proportional Counter (PSPC) pointed and survey data, the emission strength, the energy spectrum, and the fluctuation spectrum. The upper limit to the emission strength of the WHIM is 7.5 +/- 1.0 keV/(s*sq cm*sr*keV) in the 3/4 keV band, an unknown portion of which value may be due to our own Galactic halo. The spectral stape of the WHIM emission can be described as thermal emission with logT = 6.42, although the true spectrum is more likely to come from a range of temperatures. The values of emission strength and spectral shape are in reasonable agreement with hydrodynamical cosmological models. The autocorrelation function in the 0.44 keV < E < 1.21 keV band range, w(theta), for the extragalactic soft X-ray background (SXRB) which includes both the WHIM and contributions due to point sources, is approx. < 0.002 for 10 min < 0 < 20 min in the 3/4 keV band. This value is lower than the Croft et al. (2000) cosmological model by a factor of approx. 5, but is still not inconsistent with cosmological models. It is also found that the normalization of the extragalactic power law component of the soft X-ray background spectrum must be 9.5 +/- 0.9 keV/(s*sq cm*sr*keV) to be consistent with the ROSAT All-Sky Survey.

  20. Detection of the Entropy of the Intergalactic Medium: Accretion Shocks in Clusters, Adiabatic Cores in Groups

    E-print Network

    Paolo Tozzi; Caleb Scharf; Colin Norman

    2000-06-19

    The thermodynamics of the diffuse, X-ray emitting gas in clusters of galaxies is linked to the entropy level of the intra cluster medium. In particular, models that successfully reproduce the properties of local X-ray clusters and groups require the presence of a minimum value for the entropy in the center of X-ray halos. Such a minimum entropy is most likely generated by non-gravitational processes, in order to produce the observed break in self-similarity of the scaling relations of X-ray halos. At present there is no consensus on the level, the source or the time evolution of this excess entropy. In this paper we describe a strategy to investigate the physics of the heating processes acting in groups and clusters. We show that the best way to extract information from the local data is the observation of the entropy profile at large radii in nearby X-ray halos (z~0.1), both at the upper and lower extremes of the cluster mass scale. The spatially and spectrally resolved observation of such X-ray halos provides information on the mechanism of the heating. We demonstrate how measurements of the size of constant entropy (adiabatic) cores in clusters and groups can directly constrain heating models, and the minimum entropy value. We also consider two specific experiments: the detection of the shock fronts expected at the virial boundary of rich clusters, and the detection of the isentropic, low surface-brightness emission extending to radii larger than the virial ones in low mass clusters and groups. Such observations will be a crucial probe of both the physics of clusters and the relationship of non-gravitational processes to the thermodynamics of the intergalactic medium.

  1. The Search for Diffuse Intergalactic and Circumgalactic Emission with the Cosmic Origins Spectrograph

    NASA Astrophysics Data System (ADS)

    Penton, Steven

    2014-10-01

    We propose to measure the emission from the gas associated with known extragalactic UV absorbers to constrain the physical conditions and physical size of the gas. This will be accomplished through the co-addition of numerous { >75} COS QSO lines of sight, shifted in wavelength so the absorbers are coincident. The COS aperture admits light from the surrounding sky that can be separated from the point source signal to measure diffuse emission. No single observation has the sensitivity to detect these signals, but large coadditions can, unless the gas is extremely low density. We have custom extraction procedures for this project, and our intimate understanding of CalCOS, the optical performance of COS, and FUV detector systematics {scattered light, dark rate, gain sag, detector walk, etc.}, are essential to its success. Our team consists of COS IDT members, the COS PI and optical designer of COS, STScI COS calibration team members, and IGM/CGM experts. We will look for emission from HI Lya 1216A and OVI 1032A. Emission and absorption measures on a unique line of sight would normally allow for a determination of the volume density and physical size. However, since this study will produce a net emission measure from many co-added lines of sight, it will provide an average, but unique, physical insight into the nature of the gas, and in particular, indicate what fraction of this previously undetected gas is circumgalactic versus truly intergalactic in nature. We will also search for extended diffuse emission from gas not associated with absorption systems. We will also assist in testing and enabling many cutting edge additions to CalCOS which will benefit future COS users.

  2. Bringing Simulation and Observation Together to Better Understand the Intergalactic Medium

    NASA Astrophysics Data System (ADS)

    Egan, Hilary; Smith, Britton D.; O'Shea, Brian W.; Shull, J. Michael

    2014-08-01

    The methods by which one characterizes the distribution of matter in cosmological simulations is intrinsically different from how one performs the same task observationally. In this paper, we make substantial steps toward comparing simulations and observations of the intergalactic medium (IGM) in a more sensible way. We present a pipeline that generates and fits synthetic QSO absorption spectra using sight lines cast through a cosmological simulation, and simultaneously identifies structure by directly analyzing the variations in H I and O VI number density. We compare synthetic absorption spectra with a less observationally motivated, but more straightforward density threshold-based method for finding absorbers. Our efforts focus on H I and O VI to better characterize the warm/hot IGM, a subset of the IGM that is challenging to conclusively identify observationally. We find that the two methods trace roughly the same quantities of H I and O VI above observable column density limits, but the synthetic spectra typically identify more substructure in absorbers. We use both methods to characterize H I and O VI absorber properties. We find that both integrated and differential column density distributions from both methods generally agree with observations. The distribution of Doppler parameters between the two methods are similar for Ly? and compare reasonably with observational results, but while the two methods agree with each other with O VI systems, they both are systematically different from observations. We find a strong correlation between O VI baryon fraction and O VI column density. We also discuss a possible bimodality in the temperature distribution of the gas traced by O VI.

  3. The EUV Continuum of QSOs and the Ionization of the Intergalactic Medium

    NASA Astrophysics Data System (ADS)

    Telfer, R.

    2001-12-01

    We use a sample of 332 archival Hubble Spece Telescope spectra of 184 QSOs with z > 0.33, mostly from the Faint Object Spectrograph (FOS), to characterize the spectral properties of QSOs in the rest-frame extreme ultraviolet (EUV), concentrating in particular on the continuum shape at wavelengths shortward of Lyman ? . We find that the continuum of the mean composite of radio-quiet QSOs between 500 and 1200 Å can be well-described by a power law with index ? EUV = -1.57 +/- 0.17 (f? ? ? ), while for radio-loud QSOs the power-law index is ? EUV = -1.96 +/- 0.12. The extrapolation of the EUV power-law for radio-quiet QSOs is consistent with soft X-ray data, suggesting a common EUV / X-ray continuum in these objects which is likely to be a large if not dominant ionization source for the intergalactic medium (IGM). A few spectra in our sample provide data of sufficient quality and wavelength coverage to study EUV absorption lines associated with the Lyman ? forest in the redshift range 1.7 < z < 2.9. Using Keck HIRES spectra to extract the position and strength of the Lyman ? forest features, we generate composite absorption spectra from the FOS data to assess the strength of weak O V ? 630 and O IV ? 788 features as a function of H I column density. We find that O V is detected in groups of Lyman forest absorbers with median H I column densities down to 1013.6cm -2, corresponding to gas with a density only slightly above the universal mean. The weaker O IV absorption is only evident in higher column density gas, down to around 1015cm -2. We use these data along with models of the photoionization of the IGM by QSO radiation to place contraints on the oxygen abundance and ionization state of the IGM.

  4. THE OPACITY OF THE INTERGALACTIC MEDIUM DURING REIONIZATION: RESOLVING SMALL-SCALE STRUCTURE

    SciTech Connect

    Emberson, J. D.; Thomas, Rajat M.; Alvarez, Marcelo A., E-mail: emberson@astro.utoronto.ca [Canadian Institute for Theoretical Astrophysics, University of Toronto, 60 St. George St., Toronto, ON M5S 3H8 (Canada)

    2013-02-15

    Early in the reionization process, the intergalactic medium (IGM) would have been quite inhomogeneous on small scales, due to the low Jeans mass in the neutral IGM and the hierarchical growth of structure in a cold dark matter universe. This small-scale structure acted as an important sink during the epoch of reionization, impeding the progress of the ionization fronts that swept out from the first sources of ionizing radiation. Here we present results of high-resolution cosmological hydrodynamics simulations that resolve the cosmological Jeans mass of the neutral IGM in representative volumes several Mpc across. The adiabatic hydrodynamics we follow are appropriate in an unheated IGM, before the gas has had a chance to respond to the photoionization heating. Our focus is determination of the resolution required in cosmological simulations in order to sufficiently sample and resolve small-scale structure regulating the opacity of an unheated IGM. We find that a dark matter particle mass of m {sub dm} {approx}< 50 M {sub Sun} and box size of L {approx}> 1 Mpc are required. With our converged results we show how the mean free path of ionizing radiation and clumping factor of ionized hydrogen depend on the ultraviolet background flux and redshift. We find, for example at z = 10, clumping factors typically of 10-20 for an ionization rate of {Gamma} {approx} (0.3-3) Multiplication-Sign 10{sup -12} s{sup -1}, with corresponding mean free paths of {approx}3-15 Mpc, extending previous work on the evolving mean free path to considerably smaller scales and earlier times.

  5. TURBULENCE IN THE INTERGALACTIC MEDIUM: SOLENOIDAL AND DILATATIONAL MOTIONS AND THE IMPACT OF NUMERICAL VISCOSITY

    SciTech Connect

    Zhu, Weishan; Gu, Qiusheng [School of Astronomy and Space Science, Nanjing University, Nanjing, 210092 (China); Feng, Long-long [Purple Mountain Observatory, Nanjing, 210008 (China); Xia, Yinhua [School of Mathematical Sciences, University of Science and Technology of China, Hefei, Anhui 230026 (China); Shu, Chi-Wang [Division of Applied Mathematics, Brown University, Providence, RI 02912 (United States); Fang, Li-Zhi [Department of Physics, University of Arizona, Tucson, AZ 85721 (United States)

    2013-11-01

    We use a suite of cosmological hydrodynamical simulations, run by two fixed grid codes, to investigate the properties of solenoidal and dilatational motions of the intergalactic medium (IGM) and the impact of numerical viscosity on turbulence in an ?CDM universe. The codes differ only in the spatial difference discretization. We find that (1) The vortical motion grows rapidly since z = 2 and reaches ?10 km s{sup –1}-90 km s{sup –1} at z = 0. Meanwhile, the small-scale compressive ratio r{sub CS} drops from 0.84 to 0.47, indicating comparable vortical and compressive motions at z = 0. (2) Power spectra of the solenoidal velocity possess two regimes, ?k {sup –0.89} and ?k {sup –2.02}, while the total and dilatational velocity follow the scaling k {sup –1.88} and k {sup –2.20}, respectively, in the turbulent range. The IGM turbulence may contain two distinct phases, the supersonic and post-supersonic phases. (3) The non-thermal pressure support, measured by the vortical kinetic energy, is comparable with the thermal pressure for ?{sub b} ? 10-100, or T < 10{sup 5.5} K at z = 0.0. The deviation of the baryon fraction from the cosmic mean shows a preliminary positive correlation with the turbulence pressure support. (4) A relatively higher numerical viscosity would dissipate both the compressive and vortical motions of the IGM into thermal energy more effectively, resulting in less developed vorticity, remarkably shortened inertial range, and leading to a non-negligible uncertainty in the thermal history of gas accretion. Shocks in regions outside of clusters are significantly suppressed by numerical viscosity since z = 2, which may directly cause the different levels of turbulence between the two codes.

  6. THE TEMPERATURE-DENSITY RELATION IN THE INTERGALACTIC MEDIUM AT REDSHIFT (z) = 2.4

    SciTech Connect

    Rudie, Gwen C.; Steidel, Charles C. [Cahill Center for Astronomy and Astrophysics, California Institute of Technology, MS 249-17, Pasadena, CA 91125 (United States); Pettini, Max, E-mail: gwen@astro.caltech.edu [Institute of Astronomy, Madingley Road, Cambridge CB3 0HA (United Kingdom)

    2012-10-01

    We present new measurements of the temperature-density (T-{rho}) relation for neutral hydrogen in the 2.0 < z < 2.8 intergalactic medium (IGM) using a sample of {approx}6000 individual H I absorbers fitted with Voigt profiles constrained in all cases by multiple Lyman series transitions. We find model-independent evidence for a positive correlation between the column density of H I (N{sub HI}) and the minimum observed velocity width of absorbers (b{sub min}). With minimal interpretation, this implies that the T-{rho} relation in the IGM is not 'inverted', contrary to many recent studies. Fitting b{sub min} as a function of N{sub HI} results in line-width-column-density dependence of the form b{sub min} = b{sub 0}(N{sub HI}/N{sub HI,0}){sup {Gamma}-1} with a minimum line width at mean density ({rho}/{rho}-bar = 1, N{sub HI,0} = 10{sup 13.6} cm{sup -2}) of b{sub 0} = 17.9 {+-} 0.2 km s{sup -1} and a power-law index of ({Gamma} - 1) = 0.15 {+-} 0.02. Using analytic arguments, these measurements imply an 'equation of state' for the IGM at (z) = 2.4 of the form T=T{sub 0} ({rho}/{rho}-bar){sup {gamma}-1} with a temperature at mean density of T{sub 0} = [1.94 {+-} 0.05] Multiplication-Sign 10{sup 4} K and a power-law index ({gamma} - 1) = 0.46 {+-} 0.05.

  7. THE STATE OF STAR FORMATION AND THE INTERGALACTIC MEDIUM AT z {approx} 6

    SciTech Connect

    Cen Renyue, E-mail: cen@astro.princeton.ed [Princeton University Observatory, Princeton, NJ 08544 (United States)

    2010-12-10

    In the context of stellar reionization in the standard cold dark matter model, we analyze observations at z {approx} 6 and are able to draw three significant conclusions with respect to star formation and the state of the intergalactic medium (IGM) at z {approx} 6. (1) An initial stellar mass function (IMF) more efficient, by a factor of 10-20, in producing ionizing photons than the standard Salpeter IMF is required at z {approx} 6. This may be achieved by having either (a) a metal-enriched IMF with a lower mass cutoff of {>=}30 M{sub sun} or (b) 2%-4% of stellar mass being Population III massive metal-free stars at z {approx} 6. While there is no compelling physical reason or observational evidence to support (a), (b) could plausibly be fulfilled by continued existence of some pockets of uncontaminated, metal-free gas for star formation. (2) The volume-weighted neutral fraction of the IGM of {sub V}{approx}10{sup -4} at z = 5.8 inferred from the SDSS observations of QSO absorption spectra provides enough information to ascertain that reionization is basically complete with at most {approx}0.1%-1% of IGM that is unionized at z = 5.8. (3) Barring some extreme evolution of the IMF, the neutral fraction of the IGM is expected to rise quickly toward high redshift from the point of H II bubble percolation, with the mean neutral fraction of the IGM expected to reach 6%-12% at z = 6.5, 13%-27% at z = 7.7, and 22%-38% at z = 8.8.

  8. ANISOTROPIC GALACTIC OUTFLOWS AND ENRICHMENT OF THE INTERGALACTIC MEDIUM. II. NUMERICAL SIMULATIONS

    SciTech Connect

    Pinsonneault, Steeve; Martel, Hugo [Departement de physique, de genie physique et d'optique, Universite Laval, Quebec, QC G1K 7P4 (Canada); Pieri, Matthew M. [Department of Astronomy, Ohio State University, Columbus, OH 43210 (United States)

    2010-12-20

    We combine an analytic model for anisotropic outflows and galaxy formation with numerical simulations of large-scale structure and halo formation to study the impact of galactic outflows on the evolution of the intergalactic medium (IGM). Using this algorithm, we have simulated the evolution of a comoving volume of size (15 Mpc){sup 3} in the {Lambda}CDM universe. Using an N-body simulation starting at redshift z = 24, we follow the formation of galaxies and simulate the galactic outflows produced by these galaxies. Outflows are modeled as bipolar cones with opening angle {alpha}, which expand along the direction of least resistance. We consider five opening angles: {alpha} = 60{sup 0}, 90{sup 0}, 120{sup 0}, 150{sup 0}, and 180{sup 0} (isotropic outflows). We also consider the effect of photoionization suppression of galaxy formation by reionization at redshift z = 6. Anisotropic outflows travel preferentially into low-density regions, away from cosmological structures (filaments and pancakes) where galaxies form. These anisotropic outflows are less likely to overlap with one another than isotropic ones. They are also less likely to hit pre-galactic collapsing halos and strip them of their gas, preventing a galaxy from forming. Going from 180{sup 0} to 60{sup 0}, the number of galaxies that actually form doubles, producing twice as many outflows, and these outflows overlap to a lesser extent. As a result, the metal volume filling factor of the IGM goes from 8% for isotropic outflows up to 28% for anisotropic ones. High-density regions are more efficiently enriched than low-density ones ({approx}80% compared to {approx}20% by volume), even though most enriched regions are low densities. Increasing the anisotropy of outflows increases the extent of enrichment at all densities, low and high. This is in part because anisotropic outflows are more numerous. When this effect is factored out, we find that the probability a galaxy will enrich systems at densities up to 10 {rho}-bar is higher for increasingly anisotropic outflows. This is interpreted as an effect of the dynamical evolution of the IGM. Anisotropic outflows expand preferentially into underdense gas, but that gas can later accrete onto overdense structures. The inclusion of photoionization greatly reduces the formation of low-mass galaxies at redshifts z < 3. The result is a decline in the physical extent of galactic outflows after z = 3 as accretion overwhelms the expansion of new outflows and reduces feedback in underdense regions.

  9. Confirmation of X-ray Absorption by Warm-Hot Intergalactic Medium in the Sculptor Wall

    NASA Astrophysics Data System (ADS)

    Fang, Taotao; Buote, David A.; Humphrey, Philip J.; Canizares, Claude R.; Zappacosta, Luca; Maiolino, Roberto; Tagliaferri, Gianpiero; Gastaldello, Fabio

    2010-05-01

    In a previous paper, we reported a 3? detection of an absorption line from the warm-hot intergalactic medium (WHIM) using the Chandra and XMM X-ray grating spectra of the blazar H2356-309, the sight line of which intercepts the Sculptor Wall, a large-scale superstructure of galaxies at z ~ 0.03. To verify our initial detection, we obtained a deep (500 ks), follow-up exposure of H2356-309 as part of the Cycle-10 Chandra Large Project Program. From a joint analysis of the Cycle-10 and previous (Cycle-8) Chandra grating data we detect the redshifted O VII WHIM line at a significance level of 3.4?, a substantial improvement over the 1.7? level reported previously when using only the Cycle-8 data. The significance increases to 4.0? when the existing XMM grating data are included in the analysis, thus confirming at higher significance the existence of the line at the redshift of the Sculptor Wall with an equivalent width of 28.5 ± 10.5 mÅ (90% confidence). We obtain a 90% lower limit on the O VII column density of 0.8 × 1016 cm-2 and a 90% upper limit on the Doppler b parameter of 460 km s-1. Assuming the absorber is uniformly distributed throughout the ~15 Mpc portion of the blazar's sight line that intercepts the Sculptor Wall, that the O VII column density is ?2 × 1016 cm-2 (corresponding to b >~ 150 km -1 where the inferred column density is only weakly dependent on b), and that the oxygen abundance is 0.1 solar, we estimate a baryon over-density of ~30 for the WHIM, which is consistent with the peak of the WHIM mass fraction predicted by cosmological simulations. The clear detection of O VII absorption in the Sculptor Wall demonstrates the viability of using current observatories to study WHIM in the X-ray absorption spectra of blazars behind known large-scale structures.

  10. The evolution of the intergalactic medium and the formation of galaxies

    NASA Astrophysics Data System (ADS)

    Faucher-Giguere, Claude-Andre

    Galaxies form out of the collapse of dense regions of the intergalactic medium (IGM) and continued accretion from the latter fuels star formation across cosmic time At the same time, galaxies fundamentally affect the evolution of the IGM through ionizing, thermal, mechanical, and chemical feedback. The interplay between the IGM and galaxies is therefore central to a holistic understanding of both phenomena. This thesis addresses aspects of this connection in a series of investigations combining empirical input with analytic and numerical theory. After measuring the evolution of the effective Lyalpha optical depth of the IGM between z=2 and z=4.2 from a sample of 86 quasar spectra in chapter 2, we synthesize in chapter 3 the implications of this measurement for the evolution of the cosmic ionizing background and its sources, quasars and galaxies. The empirical constraints thus obtained serve as the basis for a new calculation of the evolution of the spectrum of the ionizing background versus redshift in chapter 4. As the ionizing background spectrum is a fundamental ingredient to metal abundance studies and hydrodynamical simulations, this new model will allow more accurate studies of both the IGM and galaxy formation. We also present in this chapter analytic models of the effects of HeII reionization on the spectrum of the ionizing background and on the thermal history of the IGM. In chapter 5, we focus more specifically on the assembly of galaxies and its observational signatures. We introduce a new three-dimensional Lyalpha radiative transfer code, alphaRT, and for the first time combine it with hydrodynamical simulations to predict the properties of the cooling radiation released by the cold accretion that dominates the baryonic build up of galaxies. In addition to predicting the morphologies and spectra of the cold streams, we find that the predicted Lyalpha cooling luminosities are critically sensitive to the thermal state of the self-shielded gas, which has not previously been adequately modeled. Using a simple approximation for the self-consistent thermal evolution of the dense gas in the simulations, we obtain the most robust cooling luminosity predictions to date.

  11. Intergalactic and galactic clouds on the line of sight to SN 1993J in M81 seen in IUE spectra

    NASA Technical Reports Server (NTRS)

    De Boer, K. S.; Pascual, P. Rodriguez; Wamsteker, W.; Sonneborn, G.; Fransson, C.; Bomans, D. J.; Kirshner, R. P.

    1993-01-01

    High resolution IUE spectra of SN 1993J in M81 show the existence of several clouds on the line of sight. These include local galactic gas at 0 km/s, gas in M81 at -130 km/s, a cloud in the halo in of the Milky Way near -45 km/s, and an intergalactic cloud near +140 km/s. Arguments for each of these locations are given. There is little gas in M81 in front of SN 1993J and no detectable CIV at or near -130 km/s. The gas of the halo of the Milky Way shows a large amount of CIV and SiIV. The intergalactic cloud shows a large velocity width extending from +100 km/s to +200 km/s and is very prominent in the absorption lines of AlIII, SiIV, and CIV. It may be related to energetic events in the M81 group galaxies.

  12. PROBING THE INTERGALACTIC MEDIUM/GALAXY CONNECTION. V. ON THE ORIGIN OF Ly? AND O VI ABSORPTION AT z < 0.2

    E-print Network

    Prochaska, J. Xavier

    We analyze the association of galaxies with Ly? and O VI absorption, the most commonly detected transitions of the low-z intergalactic medium (IGM), in the fields of 14 quasars with z[subscript em] = 0.06–0.57. Confirming ...

  13. Reionization in a cold dark matter universe: The feedback of galaxy formation on the intergalactic medium

    NASA Technical Reports Server (NTRS)

    Shapiro, Paul R.; Giroux, Mark L.; Babul, Arif

    1994-01-01

    We study the coupled evolution of the intergalactic medium (IGM) and the emerging structure in the universe in the context of the cold dark matter (CDM) model, with a special focus on the consequences of imposing reionization and the Gunn-Peterson constraint as a boundary condition on the model. We have calculated the time-varying density of the IGM by coupling our detailed, numerical calculations of the thermal and ionization balance and radiative transfer in a uniform, spatially averaged IGM of H and He, including the mean opacity of an evolving distribution of gas clumps which correspond to quasar absorption line clouds, to the linearized equations for the growth of density fluctuations in both the gaseous and dark matter components in a CDM universe. We use the linear growth equations to identify the fraction of the gas which must have collapsed out at each epoch, an approach similar in spirit to the so-called Press-Schechter formalism. We identify the IGM density with the uncollapsed baryon fraction. The collapsed fraction is postulated to be a source of energy injection into the IGM, by radiation or bulk hydrodynamical heating (e.g., via shocks) or both, at a rate which is marginally enough to satisfy the Gunn-Peterson constraint at z less than 5. Our results include the following: (1) We find that the IGM in a CDM model must have contained a substantial fraction of the total baryon density of the universe both during and after its reionization epoch. (2) As a result, our previous conclusion that the observed Quasi-Stellar Objects (QSOs) at high redshift are not sufficient to ionize the IGM enough to satisfy the Gunn-Peterson constraint is confirmed. (3) We predict a detectable He II Gunn-Peterson effect at 304(1 + z) A in the spectra of quasars at a range of redshift z greater than or approx. 3, depending on the nature of the sources of IGM reionization. (4) We find, moreover, that a CDM model with high bias parameter b (i.e., b greater than or approx. 2) cannot account for the baryon content of the universe at z approximately 3 observed in quasar absorption line gas unless Omega (sub B) significantly exceeds the maximum value allowed by big bang nucleocynthesis. (5) For a CDM model with bias parameter within the allowed range of (lower) values, the lower limit to Omega(sub B) imposed by big bang nucleosynthesis (Omega(sub B) h(sup 2) greater than or equal to 0.01) combines with our results to yield the minimum IGM density for the CDM fodel. For CDM with b = 1 (Cosmic Background Explorer (COBE) normalization), we find Omega(sub IGM)(sup min) (z approximately 4) approx. equal 0.02-0.03, and Omega(sub IGM)(sup min)(z approximately 0) approx. equal 0.005-0.03, depending upon the nature of the sources of IGM reionization. (6) In general, we find that self-consistent reionization of the IGM by the collapsed baryon fraction has a strong effect on the rate of collapse. (7) As a further example, we show that the feedback effect on the IGM of energy release by the collapsed baryon fraction may explain the slow evolution of the observed comoving QSO number density between z = 5 and z = 2, followed by the sharp decline after z = 2.

  14. TURBULENT MOLECULAR GAS AND STAR FORMATION IN THE SHOCKED INTERGALACTIC MEDIUM OF STEPHAN'S QUINTET

    SciTech Connect

    Guillard, P.; Cluver, M. E.; Lisenfeld, U.; Ogle, P. M. [Spitzer Science Center (SSC), California Institute of Technology, MC 220-6, Pasadena, CA 91125 (United States); Boulanger, F.; Pineau des Forets, G. [Institut d'Astrophysique Spatiale (IAS), UMR 8617, CNRS, Universite Paris-Sud 11, Batiment 121, 91405 Orsay Cedex (France); Falgarone, E.; Gusdorf, A. [ENS, LERMA, UMR 8112, CNRS, Observatoire de Paris, 24 rue Lhomond 75005 Paris (France); Appleton, P. N. [NASAHerschel Science Center (NHSC), California Institute of Technology, Mail code 100-22, Pasadena, CA 91125 (United States); Duc, P.-A. [AIM, Unite Mixte de Recherche CEA-CNRS, Universite Paris VII, UMR 7158 (France); Xu, C. K. [Infrared Processing and Analysis Center (IPAC), JPL, Pasadena, CA 91109 (United States)

    2012-04-20

    The Stephan's Quintet (hereafter SQ) is a template source to study the impact of galaxies interaction on the physical state and energetics of their gas. We report on IRAM single-dish CO observations of the SQ compact group of galaxies. These observations follow up the Spitzer discovery of bright mid-IR H{sub 2} rotational line emission (L(H{sub 2}) Almost-Equal-To 10{sup 35} W) from warm (10{sup 2-3} K) molecular gas, associated with a 30 kpc long shock between a galaxy, NGC 7318b, and NGC 7319's tidal arm. We detect CO(1-0), (2-1) and (3-2) line emission in the inter-galactic medium (IGM) with complex profiles, spanning a velocity range of Almost-Equal-To 1000 km s{sup -1}. The spectra exhibit the pre-shock recession velocities of the two colliding gas systems (5700 and 6700 km s{sup -1}), but also intermediate velocities. This shows that much of the molecular gas has formed out of diffuse gas accelerated by the galaxy-tidal arm collision. CO emission is also detected in a bridge feature that connects the shock to the Seyfert member of the group, NGC 7319, and in the northern star forming region, SQ-A, where a new velocity component is identified at 6900 km s{sup -1}, in addition to the two velocity components already known. Assuming a Galactic CO(1-0) emission to H{sub 2} mass conversion factor, a total H{sub 2} mass of Almost-Equal-To 5 Multiplication-Sign 10{sup 9} M{sub Sun} is detected in the shock. The ratio between the warm H{sub 2} mass derived from Spitzer spectroscopy, and the H{sub 2} mass derived from CO fluxes is Almost-Equal-To 0.3 in the IGM of SQ, which is 10--100 times higher than in star-forming galaxies. The molecular gas carries a large fraction of the gas kinetic energy involved in the collision, meaning that this energy has not been thermalized yet. The kinetic energy of the H{sub 2} gas derived from CO observations is comparable to that of the warm H{sub 2} gas from Spitzer spectroscopy, and a factor Almost-Equal-To 5 greater than the thermal energy of the hot plasma heated by the collision. In the shock and bridge regions, the ratio of the PAH-to-CO surface luminosities, commonly used to measure the star formation efficiency of the H{sub 2} gas, is lower (up to a factor 75) than the observed values in star-forming galaxies. We suggest that turbulence fed by the galaxy-tidal arm collision maintains a high heating rate within the H{sub 2} gas. This interpretation implies that the velocity dispersion on the scale of giant molecular clouds in SQ is one order of magnitude larger than the Galactic value. The high amplitude of turbulence may explain why this gas is not forming stars efficiently.

  15. The Fluctuating Intergalactic Radiation Field at Redshifts z = 2.3-2.9 from He II and H I Absorption toward HE 2347-4342

    NASA Astrophysics Data System (ADS)

    Shull, J. Michael; Tumlinson, Jason; Giroux, Mark L.; Kriss, Gerard A.; Reimers, Dieter

    2004-01-01

    We provide an in-depth analysis of the He II and H I absorption in the intergalactic medium (IGM) at redshifts z=2.3-2.9 toward HE 2347-4342, using spectra from the Far Ultraviolet Spectroscopic Explorer and the Ultraviolet-Visual Echelle Spectrograph on the Very Large Telescope. Following up on our earlier study, we focus here on two major topics: (1) small-scale variability (?z~10-3) in the ratio ?=N(HeII)/N(HI) and (2) an observed correlation of high-? absorbers (soft radiation fields) with voids in the (H I) Ly? distribution. These effects may reflect fluctuations in the ionizing sources on scales of 1 Mpc, together with radiative transfer through a filamentary IGM whose opacity variations control the penetration of 1-5 ryd radiation over 30-40 Mpc distances. Given the photon statistics and backgrounds, we can measure optical depths over the ranges 0.1200 may require additional contributions from starburst galaxies, heavily filtered quasar radiation, or density variations. Regions with ?<30 may indicate the presence of local hard sources. We find that ? is higher in ``void'' regions, where H I is weak or undetected and ~80% of the path length has ?>100. These voids may be ionized by local soft sources (dwarf starbursts) or by QSO radiation softened by escape from the active galactic nucleus cores or transfer through the ``cosmic web.'' The apparent differences in ionizing spectra may help to explain the 1.45 Gyr lag between the reionization epochs of H I (zHI~6.2+/-0.2) and He II (zHeII~2.8+/-0.2). This work is based on FUSE data obtained for the Guaranteed Time Team by the NASA-CNES-CSA FUSE mission, operated by the Johns Hopkins University under NASA contract NAS5-32985. Observations with the NASA/ESA Hubble Space Telescope were supported by the Space Telescope Science Institute, operated by AURA under NASA contract NAS5-26555. The VLT/UVES observations were obtained at the Paranal Observatory of the European Southern Observatory for program 166.A-0106(A).

  16. The mass of the missing baryons in the X-ray forest of the warm-hot intergalactic medium.

    PubMed

    Nicastro, Fabrizio; Mathur, Smita; Elvis, Martin; Drake, Jeremy; Fang, Taotao; Fruscione, Antonella; Krongold, Yair; Marshall, Herman; Williams, Rik; Zezas, Andreas

    2005-02-01

    Recent cosmological measurements indicate that baryons comprise about four per cent of the total mass-energy density of the Universe, which is in accord with the predictions arising from studies of the production of the lightest elements. It is also in agreement with the actual number of baryons detected at early times (redshifts z > 2). Close to our own epoch (z < 2), however, the number of baryons detected add up to just over half (approximately 55 per cent) of the number seen at z > 2 (refs 6-11), meaning that about approximately 45 per cent are 'missing'. Here we report a determination of the mass-density of a previously undetected population of baryons, in the warm-hot phase of the intergalactic medium. We show that this mass density is consistent, within the uncertainties, with the mass density of the missing baryons. PMID:15690033

  17. TeV gamma rays from 3C 279 - A possible probe of origin and intergalactic infrared radiation fields

    NASA Technical Reports Server (NTRS)

    Stecker, F. W.; De Jager, O. C.; Salamon, M. H.

    1992-01-01

    The gamma-ray spectrum of 3C 279 during 1991 June exhibited a near-perfect power law between 50 MeV and over 5 GeV with a differential spectral index of -(2.02 +/- 0.07). If extrapolated, the gamma-ray spectrum of 3C 279 should be easily detectable with first-generation air Cerenkov detectors operating above about 0.3 TeV provided there is no intergalactic absorption. However, by using model-dependent lower and upper limits for the extragalactic infrared background radiation field, a sharp cutoff of the 3C 279 spectrum is predicted at between about 0.1 and about 1 TeV. The sensitivity of present air Cerenkov detectors is good enough to measure such a cutoff, which would provide the first opportunity to obtain a measurement of the extragalactic background infrared radiation field.

  18. THE LAST EIGHT-BILLION YEARS OF INTERGALACTIC C IV EVOLUTION

    E-print Network

    Cooksey, Kathy

    We surveyed the Hubble Space Telescope UV spectra of 49 low-redshift quasars for z < 1 C IV candidates, relying solely on the characteristic wavelength separation of the doublet. After consideration of the defining traits ...

  19. The Properties of Low Redshift Intergalactic O VI Absorbers Determined from High S/N Observations of 14 QSOs with the Cosmic Origins Spectrograph

    NASA Astrophysics Data System (ADS)

    Savage, B. D.; Kim, T.-S.; Wakker, B. P.; Keeney, B.; Shull, J. M.; Stocke, J. T.; Green, J. C.

    2014-05-01

    We report on the observed properties of the plasma revealed through high signal-to-noise observations of 54 intervening O VI absorption systems containing 85 O VI and 133 H I components in a blind survey of 14 QSOs observed at ~18 km s-1 resolution with the Cosmic Origins Spectrograph over a redshift path of 3.52 at z < 0.5. Simple systems with one or two H I components and one O VI component comprise 50% of the systems. For a sample of 45 well-aligned absorption components where the temperature can be estimated, we find evidence for cool photoionized gas in 31 (69%) and warm gas (6 > log T > 5) in 14 (31%) of the components. The total hydrogen content of the 14 warm components can be estimated from the temperature and the measured value of log N(H I). The very large implied values of log N(H) range from 18.38 to 20.38 with a median of 19.35. The metallicity, [O/H], in the 6 warm components with log T > 5.45 ranges from -1.93 to 0.03 with a median value of -1.0 dex. Ground-based galaxy redshift studies reveal that most of the absorbers we detect sample gas in the intergalactic medium extending 200 to 600 kpc beyond the closest associated galaxy. For the warm aligned O VI absorbers, we estimate ?b(O VI)Warm = 0.0019 ± 0.0005 which corresponds to (4.1 ± 1.1)% of the baryons at low z. The warm plasma traced by the aligned O VI and H I absorption contains nearly as many baryons as are found in galaxies. Based on observations obtained with the NASA/ESA Hubble Space Telescope, which is operated by the Association of Universities for Research in Astronomy, Inc. under NASA contract NAS5-2655, and the NASA-CNES/ESA Far-Ultraviolet Spectroscopic Explorer mission operated by Johns Hopkins University, supported by NASA contract NAS 05-32885.

  20. The thermal history of the intergalactic medium down to redshift z = 1.5: a new curvature measurement

    NASA Astrophysics Data System (ADS)

    Boera, Elisa; Murphy, Michael T.; Becker, George D.; Bolton, James S.

    2014-07-01

    According to the photoheating model of the intergalactic medium (IGM), He II reionization is expected to affect its thermal evolution. Evidence for additional energy injection into the IGM has been found at 3 ? z ? 4, though the evidence for the subsequent fall-off below z ˜ 2.8 is weaker and depends on the slope of the temperature-density relation, ?. Here we present, for the first time, an extension of the IGM temperature measurements down to the atmospheric cut-off of the H I Lyman-? (Ly?) forest at z ? 1.5. Applying the curvature method on a sample of 60 Ultraviolet and Visual Echelle Spectrograph (UVES) spectra we investigated the thermal history of the IGM at z < 3 with precision comparable to the higher redshift results. We find that the temperature of the cosmic gas traced by the Ly? forest [T(bar{? })] increases for increasing overdensity from T(bar{? })˜ 22670 to 33740 K in the redshift range z ˜ 2.8-1.6. Under the assumption of two reasonable values for ?, the temperature at the mean density (T0) shows a tendency to flatten at z ? 2.8. In the case of ? ˜ 1.5, our results are consistent with previous ones which indicate a falling T0 for redshifts z ? 2.8. Finally, our T(bar{? }) values show reasonable agreement with moderate blazar heating models.

  1. Towards the statistical detection of the warm-hot intergalactic medium in inter-cluster filaments of the cosmic web

    E-print Network

    Tejos, Nicolas; Crighton, Neil H M; Morris, Simon L; Werk, Jessica K; Theuns, Tom; Padilla, Nelson; Bielby, Rich M; Finn, Charles W

    2015-01-01

    [Abridged] Modern analyses of structure formation predict a universe tangled in a cosmic web of dark matter and diffuse baryons. These theories further predict that by the present day, a significant fraction of the baryons will be shock-heated to $T \\sim 10^{5}-10^{7}$K yielding a warm-hot intergalactic medium (WHIM), but whose actual existence has eluded a firm observational confirmation. We have designed a novel experiment to search for signatures of the WHIM, by targeting the putative filaments connecting galaxy clusters. Here, we detail the experimental design and report on our first study of a remarkable QSO sightline, that passes within $\\Delta d 50$ km/s) and OVI absorption lines within $\\Delta v < 1000$ km/s from the cluster-pairs redshifts, corresponding to $\\sim 2$, $\\sim 2$, $\\sim 6$ and $\\sim 4$ times their field expectations, respectively. We also report on covering fractions, $f_c$, of gas close to cluster-pairs, and find that the $f_c$ of BLAs are $\\sim 4-7$ times higher than the random expe...

  2. A Snapshot Survey of AGNS/QSOS for Intergalactic Medium Studies

    NASA Technical Reports Server (NTRS)

    Sonneborn, George (Technical Monitor); Sembach, George

    2005-01-01

    This spectroscopic program with the Far Ultraviolet Spectroscopic Explorer (FUSE) program was designed to identify ultraviolet-bright active galactic nuclei (AGNs) and quasi-stellar objects (QSOs) for follow-up spectroscopy with FUSE and the Hubble Space Telescope (HST). All of the FUSE spectra obtained for this snapshot program (FUSE identifier D808) have been examined for data quality and flux levels. As expected, only a small number of objects observed (4/19) have flux levels suitable for follow-up spectroscopy. A portion of our effort in this program was devoted to comparing the spectra obtained in these snapshot exposures to others to determine if the spectra could be used for detailed scientific analyses. The resulting effort demonstrated that some of the brighter sources are relatively stable (non- variable), as determined through comparisons of the spectra at multiple epochs. For these brighter sources, the exposure times are simply too short to perform meaningful detailed analyses. Comparisons of the absorption lines in these spectra with those of higher signal-to-noise spectra, like those of PG1116+215 and H1821+643, showed that many of the lines of interest could not be characterized adequately at the S/N levels reached in the short snapshot exposures. As a result, the FUSE D808 observations are suitable only for their original purpose - flux determination. Several bright objects identified as part of this program include: HE0153-4520, flux >2x10E-14 erg cm^-2s^-1 at 1000 Angstroms IRASF04250-5718, flux >4x10E-14 erg cm^-2s^-1 A^-1 at 1000 Angstroms RXJ2154.1-4414, flux > 1.6x10E-14 erg cm^-2s^-1 A^-1 at 1000 Angstroms S50716+714, flux >2.5x10E-14 erg cm^-2s^-1 A^-1 at 1000 Angstroms. All of these objects have been incorporated into the primary target lists for the HST Cosmic Origins Spectrograph. Identifying such objects for follow-up observations with HST/COS was the primary goal of this program, so the program wa successful. In addition, some of the objects were included in proposed target lists for future FUSE observations. Given that the state of the FUSE observatory is uncertain at this time, it is unknown whether anyjof htese objects will be re-observed with FUSE. The results of this program have been communicated to the astronomical community via email and by word of mouth since the resuts in and of themselves do not warrant publication in an astronomical journal. However, these lists will be maintained for future observers. The data are archived in the Multi-Mission Archive at the Space Telescioe Science INstitute.

  3. THE NATURE OF THE WARM/HOT INTERGALACTIC MEDIUM. I. NUMERICAL METHODS, CONVERGENCE, AND O VI ABSORPTION

    SciTech Connect

    Smith, Britton D.; Hallman, Eric J.; Shull, J. Michael [Center for Astrophysics and Space Astronomy, Department of Astrophysical and Planetary Sciences, 389 UCB, University of Colorado, Boulder, CO 80309 (United States); O'Shea, Brian W., E-mail: britton.smith@colorado.edu, E-mail: michael.shull@colorado.edu [Department of Physics and Astronomy, Michigan State University, East Lansing, MI 48824 (United States)

    2011-04-10

    We perform a series of cosmological simulations using Enzo, an Eulerian adaptive-mesh refinement, N-body + hydrodynamical code, applied to study the warm/hot intergalactic medium (WHIM). The WHIM may be an important component of the baryons missing observationally at low redshift. We investigate the dependence of the global star formation rate and mass fraction in various baryonic phases on spatial resolution and methods of incorporating stellar feedback. Although both resolution and feedback significantly affect the total mass in the WHIM, all of our simulations find that the WHIM fraction peaks at z {approx} 0.5, declining to 35%-40% at z = 0. We construct samples of synthetic O VI absorption lines from our highest-resolution simulations, using several models of oxygen ionization balance. Models that include both collisional ionization and photoionization provide excellent fits to the observed number density of absorbers per unit redshift over the full range of column densities (10{sup 13} cm{sup -2} {approx}< N{sub OVI} {approx}< 10{sup 15} cm{sup -2}). Models that include only collisional ionization provide better fits for high column density absorbers (N{sub OVI} {approx}> 10{sup 14} cm{sup -2}). The distribution of O VI in density and temperature exhibits two populations: one at T {approx} 10{sup 5.5} K (collisionally ionized, 55% of total O VI) and one at T {approx} 10{sup 4.5} K (photoionized, 37%) with the remainder located in dense gas near galaxies. While not a perfect tracer of hot gas, O VI provides an important tool for a WHIM baryon census.

  4. Tomography of the intergalactic medium with Ly? forests in close QSO pairs

    NASA Astrophysics Data System (ADS)

    D'Odorico, V.; Viel, M.; Saitta, F.; Cristiani, S.; Bianchi, S.; Boyle, B.; Lopez, S.; Maza, J.; Outram, P.

    2006-11-01

    We study the three-dimensional distribution of non-virialized matter at z ~ 2 using high-resolution spectra of quasi-stellar object (QSO) pairs and simulated spectra drawn from cosmological hydrodynamical simulations. We have collected the largest sample of QSO pairs ever observed with Ultraviolet and Visual Echelle Spectrograph (UVES) at the European Southern Observatory-Very Large Telescope (ESO-VLT), with angular separations between ~1 and 14arcmin. The observed correlation functions of the transmitted flux in the HI Lyman ? forest along and transverse to the lines of sight are in good agreement implying that the distortions in redshift space due to peculiar velocities are small. The clustering signal is significant up to velocity separations of ~200kms-1, or about 3h-1 comoving Mpc. The regions at lower overdensity are still clustered but on smaller scales (?v <~ 100kms-1). The observed and simulated correlation functions are compatible at the 3? level. A better concordance is obtained when only the low overdensity regions are selected for the analysis or when the effective optical depth of the simulated spectra is increased artificially, suggesting a deficiency of strong lines in the simulated spectra. We found that also a lower value of the power-law index of the temperature-density relation for the Lyman ? forest gas improves the agreement between observed and simulated results. If confirmed, this would be consistent with other observations favouring a late HeII reionization epoch (at z ~ 3). We remark the detection of a significant clustering signal in the cross-correlation coefficient at a transverse velocity separation ?v? ~ 500kms-1 whose origin needs further investigation. Based on observations collected at the European Southern Observatory Very Large Telescope, Cerro Paranal, Chile - Programs 65.O-0299(A), 68.A-0216(A), 69.A-0204(A), 69.A-0586(A), 70.A-0031(A), 166.A-0106(A). E-mail: dodorico@oats.inaf.it

  5. A model for the distribution of dark matter, galaxies, and the intergalactic medium in a cold dark matter-dominated universe

    NASA Technical Reports Server (NTRS)

    Ryu, Dongsu; Vishniac, Ethan T.; Chiang, Wei-Hwan

    1989-01-01

    The spatial distribution of the cold-dark-matter (CDM) and baryonic components of CDM-dominated cosmological models are characterized, summarizing the results of recent theoretical investigations. The evolution and distribution of matter in an Einstein-de Sitter universe on length scales small enough so that the Newtonian approximation is valid is followed chronologically, assuming (1) that the galaxies, CDM, and the intergalactic medium (IGM) are coupled by gravity, (2) that galaxies form by taking mass and momentum from the IGM, and (3) that the IGM responds to the energy input from the galaxies. The results of the numerical computations are presented in extensive graphs and discussed in detail.

  6. THE COSMOLOGICAL IMPACT OF LUMINOUS TeV BLAZARS. II. REWRITING THE THERMAL HISTORY OF THE INTERGALACTIC MEDIUM

    SciTech Connect

    Chang, Philip; Broderick, Avery E.; Pfrommer, Christoph, E-mail: aeb@cita.utoronto.ca, E-mail: pchang@cita.utoronto.ca, E-mail: christoph.pfrommer@h-its.org [Canadian Institute for Theoretical Astrophysics, 60 St. George Street, Toronto, ON M5S 3H8 (Canada)

    2012-06-10

    The universe is opaque to extragalactic very high energy gamma rays (VHEGRs, E > 100 GeV) because they annihilate and pair produce on the extragalactic background light. The resulting ultrarelativistic pairs are commonly assumed to lose energy primarily through inverse Compton scattering of cosmic microwave background (CMB) photons, reprocessing the original emission from TeV to GeV energies. In Broderick et al., we argued that this is not the case; powerful plasma instabilities driven by the highly anisotropic nature of the ultrarelativistic pair distribution provide a plausible way to dissipate the kinetic energy of the TeV-generated pairs locally, heating the intergalactic medium (IGM). Here, we explore the effect of this heating on the thermal history of the IGM. We collate the observed extragalactic VHEGR sources to determine a local VHEGR heating rate. Given the pointed nature of VHEGR observations, we estimate the correction for the various selection effects using Fermi observations of high- and intermediate-peaked BL Lac objects. As the extragalactic component of the local VHEGR flux is dominated by TeV blazars, we then estimate the evolution of the TeV blazar luminosity density by tying it to the well-observed quasar luminosity density and producing a VHEGR heating rate as a function of redshift. This heating is relatively homogeneous for z {approx}< 4, but there is greater spatial variation at higher redshift (order unity at z {approx} 6) because of the reduced number of blazars that contribute to local heating. We show that this new heating process dominates photoheating in the low-redshift evolution of the IGM and calculate the effect of this heating in a one-zone model. As a consequence, the inclusion of TeV blazar heating qualitatively and quantitatively changes the structure and history of the IGM. Due to the homogeneous nature of the extragalactic background light, TeV blazars produce a uniform volumetric heating rate. This heating is sufficient to increase the temperature of the mean density IGM by nearly an order of magnitude, and at low densities by substantially more. It also naturally produces the inverted temperature-density relation inferred by recent observations of the high-redshift Ly{alpha} forest, a feature that is difficult to reconcile with standard reionization models. Finally, we close with a discussion on the possibility of detecting this hot low-density IGM suggested by our model either directly or indirectly via the local Ly{alpha} forest, the Comptonized CMB, or free-free emission, but we find that such measurements are currently not feasible.

  7. THE COLUMN DENSITY DISTRIBUTION AND CONTINUUM OPACITY OF THE INTERGALACTIC AND CIRCUMGALACTIC MEDIUM AT REDSHIFT (z) = 2.4

    SciTech Connect

    Rudie, Gwen C.; Steidel, Charles C. [Cahill Center for Astronomy and Astrophysics, California Institute of Technology, MS 249-17, Pasadena, CA 91125 (United States); Shapley, Alice E. [Department of Astronomy, University of California, Los Angeles, 430 Portola Plaza, Los Angeles, CA 90024 (United States); Pettini, Max, E-mail: gwen@astro.caltech.edu [Institute of Astronomy, Madingley Road, Cambridge CB3 0HA (United Kingdom)

    2013-06-01

    We present new high-precision measurements of the opacity of the intergalactic and circumgalactic medium (IGM; CGM) at (z) = 2.4. Using Voigt profile fits to the full Ly{alpha} and Ly{beta} forests in 15 high-resolution high-S/N spectra of hyperluminous QSOs, we make the first statistically robust measurement of the frequency of absorbers with H I column densities 14{approx}< log (N{sub H{sub I}}/cm{sup -2}){approx}<17.2. We also present the first measurements of the frequency distribution of H I absorbers in the volume surrounding high-z galaxies (the CGM, 300 pkpc), finding that the incidence of absorbers in the CGM is much higher than in the IGM. In agreement with Rudie et al., we find that there are fractionally more high-N{sub H{sub I}} absorbers than low-N{sub H{sub I}} absorbers in the CGM compared to the IGM, leading to a shallower power law fit to the CGM frequency distribution. We use these new measurements to calculate the total opacity of the IGM and CGM to hydrogen-ionizing photons, finding significantly higher opacity than most previous studies, especially from absorbers with log (N{sub H{sub I}}/cm{sup -2}) < 17.2. Reproducing the opacity measured in our data as well as the incidence of absorbers with log (N{sub H{sub I}}/cm{sup -2})>17.2 requires a broken power law parameterization of the frequency distribution with a break near N{sub H{sub I}} Almost-Equal-To 10{sup 15} cm{sup -2}. We compute new estimates of the mean free path ({lambda}{sub mfp}) to hydrogen-ionizing photons at z{sub em} = 2.4, finding {lambda}{sub mfp} = 147 {+-} 15 Mpc when considering only IGM opacity. If instead, we consider photons emanating from a high-z star-forming galaxy and account for the local excess opacity due to the surrounding CGM of the galaxy itself, the mean free path is reduced to {lambda}{sub mfp} = 121 {+-} 15 Mpc. These {lambda}{sub mfp} measurements are smaller than recent estimates and should inform future studies of the metagalactic UV background and of ionizing sources at z Almost-Equal-To 2-3.

  8. Second generation spectrograph for the Hubble Space Telescope

    NASA Technical Reports Server (NTRS)

    Woodgate, B. E.; Boggess, A.; Gull, T. R.; Heap, S. R.; Krueger, V. L.; Maran, S. P.; Melcher, R. W.; Rebar, F. J.; Vitagliano, H. D.

    1986-01-01

    The preliminary design for the Space Telescope Imaging Spectrograph (STIS), which has been selected by NASA for definition study for future flight as a second-generation instrument on the Hubble Space Telescope (HST), is presented. STIS is a two-dimensional spectrograph that will operate from 1050 A to 11,000 A at the limiting HST resolution of 0.05 arcsec FWHM, with spectral resolutions of 100, 1200, 20,000, and 100,000 and a maximum field-of-view of 50 x 50 arcsec. Its basic operating modes include echelle model, long slit mode, slitless spectrograph mode, coronographic spectroscopy, photon time-tagging, and direct imaging. Research objectives are active galactic nuclei, the intergalactic medium, global properties of galaxies, the origin of stellar systems, stelalr spectral variability, and spectrographic mapping of solar system processes.

  9. A New Method to Directly Measure the Jeans Scale of the Intergalactic Medium Using Close Quasar Pairs

    NASA Astrophysics Data System (ADS)

    Rorai, Alberto; Hennawi, Joseph F.; White, Martin

    2013-10-01

    Although the baryons in the intergalactic medium (IGM) trace dark matter fluctuations on megaparsec scales, on smaller scales ~100 kpc, fluctuations are suppressed because the finite temperature gas is pressure supported against gravity, analogous to the classical Jeans argument. This Jeans filtering scale, which quantifies the small-scale structure of the IGM, has fundamental cosmological implications. First, it provides a thermal record of heat injected by ultraviolet photons during cosmic reionization events, and thus constrains the thermal and reionization history of the universe. Second, the Jeans scale determines the clumpiness of the IGM, a critical ingredient in models of cosmic reionization. Third, it sets the minimum mass scale for gravitational collapse from the IGM, and hence plays a pivotal role in galaxy formation. Unfortunately, it is extremely challenging to measure the Jeans scale via the standard technique of analyzing purely longitudinal Ly? forest spectra, because the thermal Doppler broadening of absorption lines along the line-of-sight, is highly degenerate with Jeans smoothing. In this work, we show that the Jeans filtering scale can be directly measured by characterizing the coherence of correlated Ly? forest absorption in close quasar pairs, with separations small enough ~100 kpc to resolve it. We present a novel technique for this purpose, based on the probability density function (PDF) of phase angle differences of homologous longitudinal Fourier modes in close quasar pair spectra. A Bayesian formalism is introduced based on the phase angle PDF, and Markov Chain Monte Carlo techniques are used to characterize the precision of a hypothetical Jeans scale measurement, and explore degeneracies with other thermal parameters governing the IGM. A semi-analytical model of the Ly? forest is used to generate a large grid (500) of thermal models from a dark matter only simulation. Our full parameter study indicates that a realistic sample of only 20 close quasar pair spectra can pinpoint the Jeans scale to ~= 5% precision, independent of the amplitude T 0 and slope ? of the temperature-density relation of the IGM T=T_0(\\rho / {\\bar{\\rho }})^{\\gamma -1}. This exquisite sensitivity arises because even long-wavelength one-dimensional Fourier modes ~10 Mpc, i.e., two orders of magnitude larger than the Jeans scale, are nevertheless dominated by projected small-scale three-dimensional (3D) power. Hence phase angle differences between all modes of quasar pair spectra actually probe the shape of the 3D power spectrum on scales comparable to the pair separation. We show that this new method for measuring the Jeans scale is unbiased and is insensitive to a battery of systematics that typically plague Ly? forest measurements, such as continuum fitting errors, imprecise knowledge of the noise level and/or spectral resolution, and metal-line absorption.

  10. A galaxy overdensity at z=0.401 associated with an X-ray emitting structure of Warm-Hot Intergalactic Medium

    E-print Network

    Mannucci, F; Zappacosta, L; Maiolino, R; Pedani, M

    2007-01-01

    We present the results of spectroscopic observations of galaxies associated with the diffuse X-ray emitting structure discovered by Zappacosta et al. (2002). By measuring the redshifts of 161 galaxies we confirm the existence of an overdensity of galaxies with projected dimensions of at least 2 Mpc, determine its spectroscopic redshift in z=0.401+/-0.002, and show that it is spatially coincident with the diffuse X-ray emission. This confirms the original claim that this X-ray emission is of extragalactic nature and is due to the Warm-Hot Intergalactic Medium (WHIM). We used this value of the redshift to compute the temperature of the emitting gas. The resulting value depends on the metallicity that is assumed for the IGM, and is constrained to be between 0.3 and 0.6 keV for metallicities between 0.05 and 0.3 solar, in good agreement with the expectations from the WHIM.

  11. Space Station

    NASA Technical Reports Server (NTRS)

    Anderton, D. A.

    1985-01-01

    The official start of a bold new space program, essential to maintain the United States' leadership in space was signaled by a Presidential directive to move aggressively again into space by proceeding with the development of a space station. Development concepts for a permanently manned space station are discussed. Reasons for establishing an inhabited space station are given. Cost estimates and timetables are also cited.

  12. Space Odyssey

    Microsoft Academic Search

    Serge Brunier

    2002-01-01

    In only forty years the exploration of space has become one of humanity's preeminent achievements. Space Odyssey follows the greatest moments of this saga and tells the tale of the four hundred men and women who have been into space. The journey begins with the pioneers of life in space, those first humans sent into Earth orbit and the legendary

  13. Space Day

    NSDL National Science Digital Library

    Space Day '98, to be held on May 21, 1998, celebrates and honors the people who have made space exploration possible. The highlight of the Space Day homepage, maintained by Lockheed Martin Corporation, will be a live interactive webcast all day on May 21. Features of the webcast include experts in the fields of space discussing issues ranging from global collaboration to mysteries that remain. In addition to the webcast, the Space Day '98 home page provides resources for teachers and the curious alike. Mission: Fun allows visitors to test their space knowledge through interactive Shockwave games and quizzes while Teachers' Space provides educators with downloadable lesson plans (Adobe Acrobat [.pdf] format).

  14. THE SIZE AND ORIGIN OF METAL-ENRICHED REGIONS IN THE INTERGALACTIC MEDIUM FROM SPECTRA OF BINARY QUASARS

    SciTech Connect

    Martin, Crystal L.; Fournier, Amanda P. [Department of Physics, University of California, Santa Barbara, CA 93106 (United States); Scannapieco, Evan [School of Earth and Space Exploration, Arizona State University, P.O. Box 871404, Tempe, AZ 85287-1404 (United States); Ellison, Sara L. [Department of Physics and Astronomy, University of Victoria, Victoria, British Columbia, V8P 1A1 (Canada); Hennawi, Joseph F. [Department of Astronomy, 601 Campbell Hall, University of California, Berkeley, CA 94720-3411 (United States); Djorgovski, S. G., E-mail: cmartin@physics.ucsb.ed [Division of Physics, Mathematics, and Astronomy, California Institute of Technology, Pasadena, CA 91125 (United States)

    2010-09-20

    We present tomography of the circum-galactic metal distribution at redshift 1.7-4.5 derived from echellete spectroscopy of binary quasars. We find C IV systems at similar redshifts in paired sightlines more often than expected for sightline-independent redshifts. As the separation of the sightlines increases from 36 kpc to 907 kpc, the amplitude of this clustering decreases. At the largest separations, the C IV systems cluster similar to the Lyman-break galaxies studied by Adelberger et al. in 2005. The C IV systems are significantly less correlated than these galaxies, however, at separations less than R{sub 1} {approx_equal} 0.42 {+-} 0.15 h {sup -1} comoving Mpc. Measured in real space, i.e., transverse to the sightlines, this length scale is significantly smaller than the break scale estimated previously from the line-of-sight correlation function in redshift space by Scannapieco et al. in 2006. Using a simple model, we interpret the new real-space measurement as an indication of the typical physical size of enriched regions. We adopt this size for enriched regions and fit the redshift-space distortion in the line-of-sight correlation function. The fitted velocity kick is consistent with the peculiar velocity of galaxies as determined by the underlying mass distribution and places an upper limit on the average outflow (or inflow) speed of metals. The implied timescale for dispersing metals is larger than the typical stellar ages of Lyman-break galaxies, and we argue that enrichment by galaxies at z {>=} 4.3 played a greater role in dispersing metals. To further constrain the growth of enriched regions, we discuss empirical constraints on the evolution of the C IV correlation function with cosmic time. This study demonstrates the potential of tomography for measuring the metal enrichment history of the circum-galactic medium.

  15. Space prospects. [european space programs

    NASA Technical Reports Server (NTRS)

    1980-01-01

    A strategy for keeping the Common Market's space effort independent of and competitive with NASA and the space shuttle is discussed. Limited financing is the chief obstacle to this. Proposals include an outer space materials processing project and further development of the Ariane rocket. A manned space program is excluded for the foreseeable future.

  16. Space Missions

    NSDL National Science Digital Library

    Randy Russell

    2004-05-10

    With three levels to choose from on each page - beginner, intermediate or advanced - this site provides in formation on past and current exploration ideas and achievements. The advances science has made in the space exploration area, such as having a permanent space station in space and the hundreds of probes, satellite, and space shuttles that have been launched. Advanced telescopes have given scientists the opportunity to see far beyond we ever imagined, and new explorations are found every day. Also featured are details about the International space station and what kinds of experiments scientists do in outer space.

  17. Space Basics

    NASA Technical Reports Server (NTRS)

    Herbert, Dexter (editor)

    1991-01-01

    In this education video series, 'Liftoff to Learning', astronauts (Bruce Melnick, Thomas Akers, William Shepherd, Robert Cabana, and Richard Richards) describe the historical beginnings of space exploration from the time of Robert H. Goddard (considered the Father of Rocketry), who, in 1929, invented the first propellant rocket, the prototype of modern liquid propellant rockets, up to the modern Space Shuttles. The questions - where is space, what is space, and how do astronauts get to, stay in, and come back from space are answered through historical footage, computer graphics, and animation. The space environment effects, temperature effects, and gravitational effects on the launching, orbiting, and descent of the Shuttles are discussed. Included is historical still photos and film footage of past space programs and space vehicles.

  18. Space Update

    NSDL National Science Digital Library

    2006-01-01

    This DVD includes space science images, movies and activities aligned with national standards. Includes the following sections: Astronomy, Solar System, Sky Tonight, and Space Weather models, which run separately or as a linked system, plus Space Events. It is safe for unattended use and suitable for museums or school libraries. Images can be updated without need of an open web browser.

  19. Space Survey

    NSDL National Science Digital Library

    This is a lesson about society and space exploration. Learners will survey the public about their different opinions about space exploration and the use of robotics in space exploration. Then they will represent and analyze the results. This is lesson 5 of 16 in the MarsBots learning module.

  20. Space Sciences

    NSDL National Science Digital Library

    Space Sciences contains information on the solar system, the Sun, Moon, and formation of the Earth as well as a wallpaper gallery of astronomical images. There are links to real-time astronomical data, a virtual tour of the International Space Station, star charts, the NASA space launch schedule, maps of the night sky, satellite data, an Earth and Moon viewer, and more.

  1. Space Froggy

    NSDL National Science Digital Library

    2010-01-01

    Help Captain Space Froggy and his family escape from a top secret lab located on the Space Station "Fluffy" above the Earth. To escape they must first cross the busy docking ramp and then traverse deep space landing on one of the transporter pads.

  2. A LYMAN BREAK GALAXY IN THE EPOCH OF REIONIZATION FROM HUBBLE SPACE TELESCOPE GRISM SPECTROSCOPY

    SciTech Connect

    Rhoads, James E.; Malhotra, Sangeeta; Cohen, Seth; Zheng Zhenya [School of Earth and Space Exploration, Arizona State University, Tempe, AZ 85287 (United States); Stern, Daniel [Jet Propulsion Laboratory, California Institute of Technology, 4800 Oak Grove Drive, Pasadena, CA 91109 (United States); Dickinson, Mark [National Optical Astronomy Observatory, Tucson, AZ (United States); Pirzkal, Norbert; Grogin, Norman; Koekemoer, Anton; Peth, Michael A. [Space Telescope Science Institute, Baltimore, MD (United States); Spinrad, Hyron [University of California, Berkeley, CA (United States); Reddy, Naveen [University of California, Riverside, CA (United States); Hathi, Nimish [Observatories of the Carnegie Institution of Washington, Pasadena, CA (United States); Budavari, Tamas [Johns Hopkins University, Baltimore, MD (United States); Ferreras, Ignacio [Mullard Space Science Laboratory, University College London, Holmbury St Mary, Dorking, Surrey RH5 6NT (United Kingdom); Gardner, Jonathan P. [NASA Goddard Space Flight Center, Astrophysics Science Division, Observational Cosmology Laboratory, Code 665, Greenbelt, MD 20771 (United States); Gronwall, Caryl [Department of Astronomy and Astrophysics, and Institute for Gravitation and the Cosmos, The Pennsylvania State University, University Park, PA 16802 (United States); Haiman, Zoltan [Columbia University, New York, NY (United States); Kuemmel, Martin [Universitaets-Sternwarte Muenchen, Scheinerstr. 1, D-81679 Muenchen (Germany); Meurer, Gerhardt, E-mail: James.Rhoads@asu.edu [International Centre for Radio Astronomy Research, University of Western Australia, M468, 35 Stirling Highway, Crawley, WA 6009 (Australia); and others

    2013-08-10

    We present observations of a luminous galaxy at z = 6.573-the end of the reionization epoch-which has been spectroscopically confirmed twice. The first spectroscopic confirmation comes from slitless Hubble Space Telescope Advanced Camera for Surveys grism spectra from the PEARS survey (Probing Evolution And Reionization Spectroscopically), which show a dramatic continuum break in the spectrum at rest frame 1216 A. The second confirmation is done with Keck + DEIMOS. The continuum is not clearly detected with ground-based spectra, but high wavelength resolution enables the Ly{alpha} emission line profile to be determined. We compare the line profile to composite line profiles at z = 4.5. The Ly{alpha} line profile shows no signature of a damping wing attenuation, confirming that the intergalactic gas is ionized at z = 6.57. Spectra of Lyman breaks at yet higher redshifts will be possible using comparably deep observations with IR-sensitive grisms, even at redshifts where Ly{alpha} is too attenuated by the neutral intergalactic medium to be detectable using traditional spectroscopy from the ground.

  3. Space Commercialization

    NASA Technical Reports Server (NTRS)

    Martin, Gary L.

    2011-01-01

    A robust and competitive commercial space sector is vital to continued progress in space. The United States is committed to encouraging and facilitating the growth of a U.S. commercial space sector that supports U.S. needs, is globally competitive, and advances U.S. leadership in the generation of new markets and innovation-driven entrepreneurship. Energize competitive domestic industries to participate in global markets and advance the development of: satellite manufacturing; satellite-based services; space launch; terrestrial applications; and increased entrepreneurship. Purchase and use commercial space capabilities and services to the maximum practical extent Actively explore the use of inventive, nontraditional arrangements for acquiring commercial space goods and services to meet United States Government requirements, including measures such as public-private partnerships, . Refrain from conducting United States Government space activities that preclude, discourage, or compete with U.S. commercial space activities. Pursue potential opportunities for transferring routine, operational space functions to the commercial space sector where beneficial and cost-effective.

  4. Space America's commercial space program

    NASA Technical Reports Server (NTRS)

    Macleod, N. H.

    1984-01-01

    Space America prepared a private sector land observing space system which includes a sensor system with eight spectral channels configured for stereoscopic data acquisition of four stereo pairs, a spacecraft bus with active three-axis stabilization, a ground station for data acquisition, preprocessing and retransmission. The land observing system is a component of Space America's end-to-end system for Earth resources management, monitoring and exploration. In the context of the Federal Government's program of commercialization of the US land remote sensing program, Space America's space system is characteristic of US industry's use of advanced technology and of commercial, entrepreneurial management. Well before the issuance of the Request for Proposals for Transfer of the United States Land Remote Sensing Program to the Private Sector by the US Department of Commerce, Space Services, Inc., the managing venturer of Space America, used private funds to develop and manage its sub-orbital launch of its Conestoga launch vehicle.

  5. On the connection between the intergalactic medium and galaxies: the H I-galaxy cross-correlation at z ? 1

    NASA Astrophysics Data System (ADS)

    Tejos, Nicolas; Morris, Simon L.; Finn, Charles W.; Crighton, Neil H. M.; Bechtold, Jill; Jannuzi, Buell T.; Schaye, Joop; Theuns, Tom; Altay, Gabriel; Le Fèvre, Olivier; Ryan-Weber, Emma; Davé, Romeel

    2014-01-01

    We present a new optical spectroscopic survey of 1777 `star-forming' (`SF') and 366 `non-star-forming' (`non-SF') galaxies at redshifts z ˜ 0-1 (2143 in total), 22 AGN and 423 stars, observed by instruments such as the Deep Imaging Multi-Object Spectrograph, the Visible Multi-Object Spectrograph and the Gemini Multi-Object Spectrograph, in three fields containing five quasi-stellar objects (QSOs) with Hubble Space Telescope (HST) ultraviolet spectroscopy. We also present a new spectroscopic survey of 173 `strong' (1014 ? NHI? 1017 cm-2) and 496 `weak' (1013 ? NHI < 1014 cm-2) intervening H I (Ly?) absorption-line systems at z ? 1 (669 in total), observed in the spectra of eight QSOs at z ˜ 1 by the Cosmic Origins Spectrograph and the Faint Object Spectrograph on the HST. Combining these new data with previously published galaxy catalogues such as the Very Large Telescope Visible Multi-Object Spectrograph Deep Survey and the Gemini Deep Deep Survey, we have gathered a sample of 654 H I absorption systems and 17 509 galaxies at transverse scales ?50 Mpc, suitable for a two-point correlation function analysis. We present observational results on the H I-galaxy (?ag) and galaxy-galaxy (?gg) correlations at transverse scales r? ? 10 Mpc, and the H I-H I autocorrelation (?aa) at transverse scales r? ? 2 Mpc. The two-point correlation functions are measured both along and transverse to the line of sight, ?(r?, r?). We also infer the shape of their corresponding `real-space' correlation functions, ?(r), from the projected along the line-of-sight correlations, assuming power laws of the form ?(r) = (r/r0)-?. Comparing the results from ?ag, ?gg and ?aa, we constrain the H I-galaxy statistical connection, as a function of both H I column density and galaxy star formation activity. Our results are consistent with the following conclusions: (i) the bulk of H I systems on ˜ Mpc scales have little velocity dispersion (?120 km s-1) with respect to the bulk of galaxies (i.e. no strong galaxy outflow/inflow signal is detected); (ii) the vast majority (˜100 per cent) of `strong' H I systems and `SF' galaxies are distributed in the same locations, together with 75 ± 15 per cent of `non-SF' galaxies, all of which typically reside in dark matter haloes of similar masses; (iii) 25 ± 15 per cent of `non-SF' galaxies reside in galaxy clusters and are not correlated with `strong' H I systems at scales ?2 Mpc; and (iv) >50 per cent of `weak' H I systems reside within galaxy voids (hence not correlated with galaxies), and are confined in dark matter haloes of masses smaller than those hosting `strong' systems and/or galaxies. We speculate that H I systems within galaxy voids might still be evolving in the linear regime even at scales ?2 Mpc.

  6. New limits on 21 cm epoch of reionization from paper-32 consistent with an x-ray heated intergalactic medium at z = 7.7

    SciTech Connect

    Parsons, Aaron R.; Liu, Adrian; Ali, Zaki S.; Pober, Jonathan C. [Astronomy Department, University of California, Berkeley, CA (United States); Aguirre, James E.; Moore, David F. [Department of Physics and Astronomy, University of Pennsylvania, Philadelphia, PA (United States); Bradley, Richard F. [Department of Electrical and Computer Engineering, University of Virginia, Charlottesville, VA (United States); Carilli, Chris L. [National Radio Astronomy Observatory, Socorro, NM (United States); DeBoer, David R.; Dexter, Matthew R.; MacMahon, David H. E. [Radio Astronomy Laboratory, University of California, Berkeley, CA (United States); Gugliucci, Nicole E. [Department of Astronomy, University of Virginia, Charlottesville, VA (United States); Jacobs, Daniel C. [School of Earth and Space Exploration, Arizona State University, Tempe, AZ (United States); Klima, Pat [National Radio Astronomy Observatory, Charlottesville, VA (United States); Manley, Jason R.; Walbrugh, William P. [Square Kilometer Array, South Africa Project, Cape Town (South Africa); Stefan, Irina I. [Cavendish Laboratory, Cambridge (United Kingdom)

    2014-06-20

    We present new constraints on the 21 cm Epoch of Reionization (EoR) power spectrum derived from three months of observing with a 32 antenna, dual-polarization deployment of the Donald C. Backer Precision Array for Probing the Epoch of Reionization in South Africa. In this paper, we demonstrate the efficacy of the delay-spectrum approach to avoiding foregrounds, achieving over eight orders of magnitude of foreground suppression (in mK{sup 2}). Combining this approach with a procedure for removing off-diagonal covariances arising from instrumental systematics, we achieve a best 2? upper limit of (41 mK){sup 2} for k = 0.27 h Mpc{sup –1} at z = 7.7. This limit falls within an order of magnitude of the brighter predictions of the expected 21 cm EoR signal level. Using the upper limits set by these measurements, we generate new constraints on the brightness temperature of 21 cm emission in neutral regions for various reionization models. We show that for several ionization scenarios, our measurements are inconsistent with cold reionization. That is, heating of the neutral intergalactic medium (IGM) is necessary to remain consistent with the constraints we report. Hence, we have suggestive evidence that by z = 7.7, the H I has been warmed from its cold primordial state, probably by X-rays from high-mass X-ray binaries or miniquasars. The strength of this evidence depends on the ionization state of the IGM, which we are not yet able to constrain. This result is consistent with standard predictions for how reionization might have proceeded.

  7. Probability Spaces

    NSDL National Science Digital Library

    Siegrist, Kyle

    Created by Kyle Siegrist of the University of Alabama-Huntsville, this is an online, interactive lesson on probability spaces. The resource provides examples, exercises, and applets that cover conditional probability, independence, and several modes of convergence that are appropriate for random variables. This section also covers probability space, the paradigm of a random experiment and its mathematical model as well as sample spaces, events, random variables, and probability measures. This is the second of seventeen different statistics lessons provided by Siegrist.

  8. Space microbiology.

    PubMed

    Horneck, Gerda; Klaus, David M; Mancinelli, Rocco L

    2010-03-01

    The responses of microorganisms (viruses, bacterial cells, bacterial and fungal spores, and lichens) to selected factors of space (microgravity, galactic cosmic radiation, solar UV radiation, and space vacuum) were determined in space and laboratory simulation experiments. In general, microorganisms tend to thrive in the space flight environment in terms of enhanced growth parameters and a demonstrated ability to proliferate in the presence of normally inhibitory levels of antibiotics. The mechanisms responsible for the observed biological responses, however, are not yet fully understood. A hypothesized interaction of microgravity with radiation-induced DNA repair processes was experimentally refuted. The survival of microorganisms in outer space was investigated to tackle questions on the upper boundary of the biosphere and on the likelihood of interplanetary transport of microorganisms. It was found that extraterrestrial solar UV radiation was the most deleterious factor of space. Among all organisms tested, only lichens (Rhizocarpon geographicum and Xanthoria elegans) maintained full viability after 2 weeks in outer space, whereas all other test systems were inactivated by orders of magnitude. Using optical filters and spores of Bacillus subtilis as a biological UV dosimeter, it was found that the current ozone layer reduces the biological effectiveness of solar UV by 3 orders of magnitude. If shielded against solar UV, spores of B. subtilis were capable of surviving in space for up to 6 years, especially if embedded in clay or meteorite powder (artificial meteorites). The data support the likelihood of interplanetary transfer of microorganisms within meteorites, the so-called lithopanspermia hypothesis. PMID:20197502

  9. Space Shuttle

    NASA Technical Reports Server (NTRS)

    1976-01-01

    The design of the spacecraft is described. Focus is placed on the external tanks, the solid rocket boosters, the main engine, and the space shuttle orbiter. The logistics of the project were reviewed and included the management plan, the facilities involved in construction and testing of the space shuttle, and the benefits expected from the project.

  10. Space psychology

    NASA Technical Reports Server (NTRS)

    Parin, V. V.; Gorbov, F. D.; Kosmolinskiy, F. P.

    1974-01-01

    Psychological selection of astronauts considers mental responses and adaptation to the following space flight stress factors: (1) confinement in a small space; (2) changes in three dimensional orientation; (3) effects of altered gravity and weightlessness; (4) decrease in afferent nerve pulses; (5) a sensation of novelty and danger; and (6) a sense of separation from earth.

  11. Space Microbiology

    PubMed Central

    Horneck, Gerda; Klaus, David M.; Mancinelli, Rocco L.

    2010-01-01

    Summary: The responses of microorganisms (viruses, bacterial cells, bacterial and fungal spores, and lichens) to selected factors of space (microgravity, galactic cosmic radiation, solar UV radiation, and space vacuum) were determined in space and laboratory simulation experiments. In general, microorganisms tend to thrive in the space flight environment in terms of enhanced growth parameters and a demonstrated ability to proliferate in the presence of normally inhibitory levels of antibiotics. The mechanisms responsible for the observed biological responses, however, are not yet fully understood. A hypothesized interaction of microgravity with radiation-induced DNA repair processes was experimentally refuted. The survival of microorganisms in outer space was investigated to tackle questions on the upper boundary of the biosphere and on the likelihood of interplanetary transport of microorganisms. It was found that extraterrestrial solar UV radiation was the most deleterious factor of space. Among all organisms tested, only lichens (Rhizocarpon geographicum and Xanthoria elegans) maintained full viability after 2 weeks in outer space, whereas all other test systems were inactivated by orders of magnitude. Using optical filters and spores of Bacillus subtilis as a biological UV dosimeter, it was found that the current ozone layer reduces the biological effectiveness of solar UV by 3 orders of magnitude. If shielded against solar UV, spores of B. subtilis were capable of surviving in space for up to 6 years, especially if embedded in clay or meteorite powder (artificial meteorites). The data support the likelihood of interplanetary transfer of microorganisms within meteorites, the so-called lithopanspermia hypothesis. PMID:20197502

  12. Space Telescope.

    ERIC Educational Resources Information Center

    National Aeronautics and Space Administration, Huntsville, AL. George C. Marshall Space Flight Center.

    This pamphlet describes the Space Telescope, an unmanned multi-purpose telescope observatory planned for launch into orbit by the Space Shuttle in the 1980s. The unique capabilities of this telescope are detailed, the major elements of the telescope are described, and its proposed mission operations are outlined. (CS)

  13. Space engineering

    NASA Technical Reports Server (NTRS)

    Alexander, Harold L.

    1991-01-01

    Human productivity was studied for extravehicular tasks performed in microgravity, particularly including in-space assembly of truss structures and other large objects. Human factors research probed the anthropometric constraints imposed on microgravity task performance and the associated workstation design requirements. Anthropometric experiments included reach envelope tests conducted using the 3-D Acoustic Positioning System (3DAPS), which permitted measuring the range of reach possible for persons using foot restraints in neutral buoyancy, both with and without space suits. Much neutral buoyancy research was conducted using the support of water to simulate the weightlessness environment of space. It became clear over time that the anticipated EVA requirement associated with the Space Station and with in-space construction of interplanetary probes would heavily burden astronauts, and remotely operated robots (teleoperators) were increasingly considered to absorb the workload. Experience in human EVA productivity led naturally to teleoperation research into the remote performance of tasks through human controlled robots.

  14. Space smarts

    NASA Astrophysics Data System (ADS)

    Colucci, Frank

    1991-02-01

    A review is presented of design and development work in space data processors at the Honeywell Space Systems Group in Florida. Space computers, some hardened for the first time against radiation from both man-made nuclear events and the natural space environment, are described. A specific illustration of this is the Space Shuttle main engine control which monitors some 120 engine parameters 50 times per second and operates the actuators that control the liquid-fueled engine through its eight minute burn. It is further pointed out that Space Station processors will be tied together by three different data buses, each with its own protocol, while the backbone of the data management system will be an optical fiber distributed data interface handling up to 100 Mbits/sec. Radiation hardening without heavy shielding can be accomplished in several ways, i.e., at the materials level, by insulating substrates which can limit the photo-currents generated by a nuclear event, and at the topological level, by spacing transistors so that photocurrents cannot concentrate at any particular node.

  15. Space making

    NASA Astrophysics Data System (ADS)

    Carlowicz, Michael

    With discoveries from Mars, the Hubble Deep Field, and Ganymede reawakening Washington's interest in space, the U.S. federal government has started fine-tuning its stance on space flight and exploration. The attention comes as prelude to a proposed November meeting to discuss astronomical and planetary discoveries, and to a rumored space summit in December between Vice President Al Gore and congressional leaders.On September 17, the House of Representatives passed by voice vote H.R. 3936, the Space Commercialization Promotion Act. A measure with strong bipartisan support, the bill officially encourages private companies to participate in the space industry and requires NASA to find more ways to work with the private sector. Updating and amending several existing U.S. policies about commerce in space, H.R. 3936 gives the Department of Transportation the authority to provide and administer licenses for commercial spacecraft to reenter American airspace from orbit and outer space. It also prods NASA to purchase scientific data about the Earth and the solar system from the private sector, whenever possible.

  16. GRB 130606A AS A PROBE OF THE INTERGALACTIC MEDIUM AND THE INTERSTELLAR MEDIUM IN A STAR-FORMING GALAXY IN THE FIRST Gyr AFTER THE BIG BANG

    SciTech Connect

    Chornock, Ryan; Berger, Edo; Lunnan, Ragnhild; Drout, Maria R.; Fong Wenfai; Laskar, Tanmoy [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States); Fox, Derek B. [Department of Astronomy and Astrophysics, Pennsylvania State University, 525 Davey Laboratory, University Park, PA 16802 (United States); Roth, Katherine C., E-mail: rchornock@cfa.harvard.edu [Gemini Observatory, 670 North Aohoku Place, Hilo, HI 96720 (United States)

    2013-09-01

    We present high signal-to-noise ratio Gemini and MMT spectroscopy of the optical afterglow of the gamma-ray burst (GRB) 130606A at redshift z = 5.913, discovered by Swift. This is the first high-redshift GRB afterglow to have spectra of comparable quality to those of z Almost-Equal-To 6 quasars. The data exhibit a smooth continuum at near-infrared wavelengths that is sharply cut off blueward of 8410 A due to absorption from Ly{alpha} at redshift z Almost-Equal-To 5.91, with some flux transmitted through the Ly{alpha} forest between 7000 and 7800 A. We use column densities inferred from metal absorption lines to constrain the metallicity of the host galaxy between a lower limit of [Si/H] {approx}> -1.7 and an upper limit of [S/H] {approx}< -0.5 set by the non-detection of S II absorption. We demonstrate consistency between the dramatic evolution in the transmission fraction of Ly{alpha} seen in this spectrum over the redshift range z = 4.9-5.85 with that previously measured from observations of high-redshift quasars. There is an extended redshift interval of {Delta}z = 0.12 in the Ly{alpha} forest at z = 5.77 with no detected transmission, leading to a 3{sigma} upper limit on the mean Ly{alpha} transmission fraction of {approx}<0.2% (or {tau}{sub GP}{sup eff} (Ly{alpha}) > 6.4). This is comparable to the lowest-redshift Gunn-Peterson troughs found in quasar spectra. Some Ly{beta} and Ly{gamma} transmission is detected in this redshift window, indicating that it is not completely opaque, and hence that the intergalactic medium (IGM) is nonetheless mostly ionized at these redshifts. We set a 2{sigma} upper limit of 0.11 on the neutral fraction of the IGM at the redshift of the GRB from the lack of a Ly{alpha} red damping wing, assuming a model with a constant neutral density. GRB 130606A thus for the first time realizes the promise of GRBs as probes of the first galaxies and cosmic reionization.

  17. GRB 130606A as a Probe of the Intergalactic Medium and the Interstellar Medium in a Star-forming Galaxy in the First Gyr after the Big Bang

    NASA Astrophysics Data System (ADS)

    Chornock, Ryan; Berger, Edo; Fox, Derek B.; Lunnan, Ragnhild; Drout, Maria R.; Fong, Wen-fai; Laskar, Tanmoy; Roth, Katherine C.

    2013-09-01

    We present high signal-to-noise ratio Gemini and MMT spectroscopy of the optical afterglow of the gamma-ray burst (GRB) 130606A at redshift z = 5.913, discovered by Swift. This is the first high-redshift GRB afterglow to have spectra of comparable quality to those of z ? 6 quasars. The data exhibit a smooth continuum at near-infrared wavelengths that is sharply cut off blueward of 8410 Å due to absorption from Ly? at redshift z ? 5.91, with some flux transmitted through the Ly? forest between 7000 and 7800 Å. We use column densities inferred from metal absorption lines to constrain the metallicity of the host galaxy between a lower limit of [Si/H] >~ -1.7 and an upper limit of [S/H] <~ -0.5 set by the non-detection of S II absorption. We demonstrate consistency between the dramatic evolution in the transmission fraction of Ly? seen in this spectrum over the redshift range z = 4.9-5.85 with that previously measured from observations of high-redshift quasars. There is an extended redshift interval of ?z = 0.12 in the Ly? forest at z = 5.77 with no detected transmission, leading to a 3? upper limit on the mean Ly? transmission fraction of lsim0.2% (or \\tau _{{GP}}^{{eff}} (Ly?) > 6.4). This is comparable to the lowest-redshift Gunn-Peterson troughs found in quasar spectra. Some Ly? and Ly? transmission is detected in this redshift window, indicating that it is not completely opaque, and hence that the intergalactic medium (IGM) is nonetheless mostly ionized at these redshifts. We set a 2? upper limit of 0.11 on the neutral fraction of the IGM at the redshift of the GRB from the lack of a Ly? red damping wing, assuming a model with a constant neutral density. GRB 130606A thus for the first time realizes the promise of GRBs as probes of the first galaxies and cosmic reionization.

  18. Intergalactic medium emission observations with the cosmic web imager. II. Discovery of extended, kinematically linked emission around SSA22 Ly? BLOB 2

    SciTech Connect

    Christopher Martin, D.; Chang, Daphne; Matuszewski, Matt; Morrissey, Patrick; Rahman, Shahin [Cahill Center for Astrophysics, California Institute of Technology, 1216 East California Boulevard, Mail Code 278-17, Pasadena, CA 91125 (United States); Moore, Anna [Caltech Optical Observatories, Cahill Center for Astrophysics, California Institute of Technology, 1216 East California Boulevard, Mail Code 11-17, Pasadena, CA 91125 (United States); Steidel, Charles C.; Matsuda, Yuichi, E-mail: cmartin@srl.caltech.edu [Cahill Center for Astrophysics, California Institute of Technology, 1216 East California Boulevard, Mail Code 249-17, Pasadena, CA 91125 (United States)

    2014-05-10

    The intergalactic medium (IGM) is the dominant reservoir of baryons, delineates the large-scale structure of the universe at low to moderate overdensities, and provides gas from which galaxies form and evolve. Simulations of a cold-dark-matter- (CDM-) dominated universe predict that the IGM is distributed in a cosmic web of filaments and that galaxies should form along and at the intersections of these filaments. While observations of QSO absorption lines and the large-scale distribution of galaxies have confirmed the CDM paradigm, the cosmic web of IGM has never been confirmed by direct imaging. Here we report our observation of the Ly? blob 2 (LAB2) in SSA22 with the Cosmic Web Imager (CWI). This is an integral field spectrograph optimized for low surface brightness, extended emission. With 22 hr of total on- and off-source exposure, CWI has revealed that LAB2 has extended Ly? emission that is organized into azimuthal zones consistent with filaments. We perform numerous tests with simulations and the data to secure the robustness of this result, which relies on data with modest signal-to-noise ratios. We have developed a smoothing algorithm that permits visualization of data cube slices along image or spectral image planes. With both raw and smoothed data cubes we demonstrate that the filaments are kinematically associated with LAB2 and display double-peaked profiles characteristic of optically thick Ly? emission. The flux is 10-20 times brighter than expected for the average emission from the IGM but is consistent with boosted fluorescence from a buried QSO or gravitation cooling radiation. Using simple emission models, we infer a baryon mass in the filaments of at least 1-4 × 10{sup 11} M {sub ?}, and the dark halo mass is at least 2 × 10{sup 12} M {sub ?}. The spatial-kinematic morphology is more consistent with inflow from the cosmic web than outflow from LAB2, although an outflow feature maybe present at one azimuth. LAB2 and the surrounding gas have significant and coaligned angular momentum, strengthening the case for their association.

  19. Intergalactic Medium Emission Observations with the Cosmic Web Imager. II. Discovery of Extended, Kinematically Linked Emission around SSA22 Ly? Blob 2

    NASA Astrophysics Data System (ADS)

    Martin, D. Christopher; Chang, Daphne; Matuszewski, Matt; Morrissey, Patrick; Rahman, Shahin; Moore, Anna; Steidel, Charles C.; Matsuda, Yuichi

    2014-05-01

    The intergalactic medium (IGM) is the dominant reservoir of baryons, delineates the large-scale structure of the universe at low to moderate overdensities, and provides gas from which galaxies form and evolve. Simulations of a cold-dark-matter- (CDM-) dominated universe predict that the IGM is distributed in a cosmic web of filaments and that galaxies should form along and at the intersections of these filaments. While observations of QSO absorption lines and the large-scale distribution of galaxies have confirmed the CDM paradigm, the cosmic web of IGM has never been confirmed by direct imaging. Here we report our observation of the Ly? blob 2 (LAB2) in SSA22 with the Cosmic Web Imager (CWI). This is an integral field spectrograph optimized for low surface brightness, extended emission. With 22 hr of total on- and off-source exposure, CWI has revealed that LAB2 has extended Ly? emission that is organized into azimuthal zones consistent with filaments. We perform numerous tests with simulations and the data to secure the robustness of this result, which relies on data with modest signal-to-noise ratios. We have developed a smoothing algorithm that permits visualization of data cube slices along image or spectral image planes. With both raw and smoothed data cubes we demonstrate that the filaments are kinematically associated with LAB2 and display double-peaked profiles characteristic of optically thick Ly? emission. The flux is 10-20 times brighter than expected for the average emission from the IGM but is consistent with boosted fluorescence from a buried QSO or gravitation cooling radiation. Using simple emission models, we infer a baryon mass in the filaments of at least 1-4 × 1011 M ?, and the dark halo mass is at least 2 × 1012 M ?. The spatial-kinematic morphology is more consistent with inflow from the cosmic web than outflow from LAB2, although an outflow feature maybe present at one azimuth. LAB2 and the surrounding gas have significant and coaligned angular momentum, strengthening the case for their association.

  20. Amazing Space

    NSDL National Science Digital Library

    Space Telescope Science Institute

    2007-12-12

    Amazing Space is a set of web-based activities primarily designed for classroom usage. All lessons are interactive and have actual photographs taken by the Hubble Space Telescope. Each activity has an overview, lesson plan, links to the National Science Education Standards, science background, and other resources and links. Downloadable worksheets are included. Students can build their own Milky Way, play galaxy games, and collect Solar System Trading Cards.

  1. Space Resources

    NASA Technical Reports Server (NTRS)

    McKay, Mary Fae (Editor); McKay, David S. (Editor); Duke, Michael S. (Editor)

    1992-01-01

    Space resources must be used to support life on the Moon and exploration of Mars. Just as the pioneers applied the tools they brought with them to resources they found along the way rather than trying to haul all their needs over a long supply line, so too must space travelers apply their high technology tools to local resources. The pioneers refilled their water barrels at each river they forded; moonbase inhabitants may use chemical reactors to combine hydrogen brought from Earth with oxygen found in lunar soil to make their water. The pioneers sought temporary shelter under trees or in the lee of a cliff and built sod houses as their first homes on the new land; settlers of the Moon may seek out lava tubes for their shelter or cover space station modules with lunar regolith for radiation protection. The pioneers moved further west from their first settlements, using wagons they had built from local wood and pack animals they had raised; space explorers may use propellant made at a lunar base to take them on to Mars. The concept for this report was developed at a NASA-sponsored summer study in 1984. The program was held on the Scripps campus of the University of California at San Diego (UCSD), under the auspices of the American Society for Engineering Education (ASEE). It was jointly managed under the California Space Inst. and the NASA Johnson Space Center, under the direction of the Office of Aeronautics and Space Technology (OAST) at NASA Headquarters. The study participants (listed in the addendum) included a group of 18 university teachers and researchers (faculty fellows) who were present for the entire 10-week period and a larger group of attendees from universities, Government, and industry who came for a series of four 1-week workshops. The organization of this report follows that of the summer study. Space Resources consists of a brief overview and four detailed technical volumes: (1) Scenarios; (2) Energy, Power, and Transport; (3) Materials; (4) Social Concerns. Although many of the included papers got their impetus from workshop discussions, most have been written since then, thus allowing the authors to base new applications on established information and tested technology. All these papers have been updated to include the authors' current work. This overview, drafted by faculty fellow Jim Burke, describes the findings of the summer study, as participants explored the use of space resources in the development of future space activities and defined the necessary research and development that must precede the practical utilization of these resources. Space resources considered included lunar soil, oxygen derived from lunar soil, material retrieved from near-Earth asteroids, abundant sunlight, low gravity, and high vacuum. The study participants analyzed the direct use of these resources, the potential demand for products from them, the techniques for retrieving and processing space resources, the necessary infrastructure, and the economic tradeoffs. This is certainly not the first report to urge the utilization of space resources in the development of space activities. In fact, Space Resources may be seen as the third of a trilogy of NASA Special Publications reporting such ideas arising from similar studies. It has been preceded by Space Settlements: A Design Study (NASA SP-413) and Space Resources and Space Settlements (NASA SP-428). And other, contemporaneous reports have responded to the same themes. The National Commission on Space, led by Thomas Paine, in Pioneering the Space Frontier, and the NASA task force led by astronaut Sally Ride, in Leadership and America's Future in Space, also emphasize expansion of the space Infrastructure; more detailed exploration of the Moon, Mars, and asteroids; an early start on the development of the technology necessary for using space resources; and systematic development of the skills necessary for long-term human presence in space. Our report does not represent any Government-authorized view or official NASA policy. NASA's official response to these challenging op

  2. BBC Space

    NSDL National Science Digital Library

    Hosted by the British Broadcasting Corporation (BBC), this site provides comprehensive information about space science. There is the latest news about space findings and issues, and what's happening in the sky for the current month. Galleries show images of the planets, Sunspots, eclipses, auroras, and more. There is a night sky section with observation notes and a constellation guide for learning more about the star patterns. 'Deep Space' covers phenomena such as black holes, wormholes, and dark matter. There is a discussion covering the possibility of life elsewhere, planets outside of our Solar System, and astrobiology. 'Origins' explores the Big Bang, from the first few seconds to the future. 'Cosmology' discusses how our ideas about the Earth and Universe have grown and continue to expand. The stars section illustrates different star types, and the life of stars from birth to death. There is also a section of brief biographies on all astronomers who have contributed to our current knowledge of space, such as Galileo, Copernicus, Ptolemy, Hubble, and many more. There are links to additional sites, as well as space games to play.

  3. Space Exploration

    NASA Technical Reports Server (NTRS)

    Davis, Jeffrey R.

    2006-01-01

    This abstract covers a one hour presentation on Space Exploration. The audience is elementary students; therefore there are few words on the slides, mostly pictures of living and working in space. The presentation opens with a few slides describing a day in the life of a space explorer. It begins with a launch, discussions of day-night cycles, eating, exercising, housekeeping, EVA, relaxation, and sleeping. The next section of the presentation shows photos of astronauts performing experiments on the ISS. Yokomi Elementary School launched this fall with the most advanced educational technology tools available in schools today. The science and technology magnet school is equipped with interactive white boards, digital projectors, integrated sound systems and several computers for use by teachers and students. The only elementary school in Fresno Unified with a science focus also houses dedicated science classrooms equipped specifically for elementary students to experience hands-on science instruction in addition to the regular elementary curriculum.

  4. Space telescope

    NASA Astrophysics Data System (ADS)

    Bulkin, B. R.

    1985-02-01

    The NASA 2.4-m aperture Space Telescope (ST) will be associated with the Space Shuttle, the Tracking and Data Relay System, the Communications Center at White Sands, the Space Telescope Operations Control Center at Goddard, and the Science Institute at Johns Hopkins University. Attention is presently given to the features of the Scientific Instruments and Optical Telescope Assembly, which encompasses the Wide Field/Planetary Camera, the Faint Object Camera, the Faint Object Spectrograph, the High Resolution Spectrograph, the High Speed Photometer, and the Fine Guidance System. The ST Support System Module and Subsystems is composed of the Thermal Control System, the Electrical Power System, the Pointing Control Subsystem, and the Onboard Instrumentation and Communication Subsystem.

  5. Entering Space

    NASA Astrophysics Data System (ADS)

    Zubrin, Robert

    The authors is giving a classification of civilisations depending on the degree of colonisation of the Earth, Solar System and Our Galaxy. The problems of: History of geographic discoveries (The great geographical discoveries during the Middle Age, the concurence of Chinnese and Europeans in this Area); The Astrophysics, such as: Asteroids, Water and Atmosphere on outer planets, Planet Mars Planet, Agriculture on outer planets, Minerals on outer planets; Cosmic flights: Fuels, Robotics, Moon (as an intermediary basis for interplanetary flights), Mars colonisation; Interstellar flights, Space research costs, strategy and tactics of the space colonisation; Policy: War and Peace, International Collaboration are discussed.

  6. Space debate

    NASA Astrophysics Data System (ADS)

    The space station is alive and well. Yet so are many of its critics. Despite a new General Accounting Office report's assertions that including Russia in the space station may add $2 billion to the project's price tag, the Senate voted last week by a 64 to 36 margin to continue the project. The vote follows the station's surprisingly big 278-155 victory in the House on June 29. Before the votes, the American Astronomical Society and the Planetary Society reportedly gave up their opposition to the station.

  7. Second Symposium on Space Industrialization. [space commercialization

    NASA Technical Reports Server (NTRS)

    Jernigan, C. M. (editor)

    1984-01-01

    The policy, legal, and economic aspects of space industrialization are considered along with satellite communications, material processing, remote sensing, and the role of space carriers and a space station in space industrialization.

  8. Found Space

    ERIC Educational Resources Information Center

    Haug, Ted; Ogurek, Douglas J.

    2006-01-01

    When education providers confront obstacles such as shrinking budgets and swelling enrollments, a multi-million-dollar new facility or major additions probably are not feasible. Converting vacant and underused buildings into school facilities enables administrators to acquire additional space quickly and cheaply. In this article, the authors…

  9. Inherit Space

    NASA Technical Reports Server (NTRS)

    Giarratano, Joseph C.; Jenks, K. C.

    1997-01-01

    The objective of the proposed research was to begin development of a unique educational tool targeted at educating and inspiring young people 12-16 years old about NASA and the Space Program. Since these young people are the future engineers, scientists and space pioneers, the nurturing of their enthusiasm and interest is of critical importance to the Nation. This summer the basic infrastructure of the tool was developed in the context of an educational game paradigm. The game paradigm has achieved remarkable success in maintaining the interest of young people in a self-paced, student-directed learning environment. This type of environment encourages student exploration and curiosity which are exactly the traits that future space pioneers need to develop to prepare for the unexpected. The Inherit Space Educational Tool is an open-ended learning environment consisting of a finite-state machine classic adventure game paradigm. As the young person explores this world, different obstacles must be overcome. Rewards will be offered such as using the flight simulator to fly around and explore Titan. This simulator was modeled on conventional Earth flight simulators but has been considerably enhanced to add texture mapping of Titan's atmosphere utilizing the latest information from the NASA Galileo Space Probe. Additional scenery was added to provide color VGA graphics of a futuristic research station on Titan as well as an interesting story to keep the youngster's attention. This summer the game infrastructure has been developed as well as the Titan Flight Simulator. A number of other enhancements are planned.

  10. Hubble space telescope/cosmic origins spectrograph observations of the quasar Q0302–003: Probing the He II reionization epoch and QSO proximity effects

    SciTech Connect

    Syphers, David; Shull, J. Michael, E-mail: David.Syphers@colorado.edu [CASA, Department of Astrophysical and Planetary Sciences, University of Colorado, Boulder, CO 80309 (United States)

    2014-03-20

    Q0302–003 (z = 3.2860 ± 0.0005) was the first quasar discovered that showed a He II Gunn-Peterson trough, a sign of incomplete helium reionization at z ? 2.9. We present its Hubble Space Telescope/Cosmic Origins Spectrograph far-UV medium-resolution spectrum, which resolves many spectral features for the first time, allowing study of the quasar itself, the intergalactic medium, and quasar proximity effects. Q0302–003 has a harder intrinsic extreme-UV spectral index than previously claimed, as determined from both a direct fit to the spectrum (yielding ?{sub ?} ? –0.8) and the helium-to-hydrogen ion ratio in the quasar's line-of-sight proximity zone. Intergalactic absorption along this sightline shows that the helium Gunn-Peterson trough is largely black in the range 2.87 < z < 3.20, apart from ionization due to local sources, indicating that helium reionization has not completed at these redshifts. However, we tentatively report a detection of nonzero flux in the high-redshift trough when looking at low-density regions, but zero flux in higher-density regions. This constrains the He II fraction to be about 1% in the low-density intergalactic medium (IGM) and possibly a factor of a few higher in the IGM as a whole, suggesting helium reionization has progressed substantially by z ? 3.1. The Gunn-Peterson trough recovers to a He II Ly? forest at z < 2.87. We confirm a transmission feature due to the ionization zone around a z = 3.05 quasar just off the sightline, and resolve the feature for the first time. We discover a similar such feature possibly caused by a luminous z = 3.23 quasar further from the sightline, which suggests that this quasar has been luminous for >34 Myr.

  11. Space Toxicology

    NASA Technical Reports Server (NTRS)

    James, John T.

    2011-01-01

    Safe breathing air for space faring crews is essential whether they are inside an Extravehicular Mobility Suit (EMU), a small capsule such as Soyuz, or the expansive International Space Station (ISS). Sources of air pollution can include entry of propellants, excess offgassing from polymeric materials, leakage of systems compounds, escape of payload compounds, over-use of utility compounds, microbial metabolism, and human metabolism. The toxicological risk posed by a compound is comprised of the probability of escaping to cause air pollution and the magnitude of adverse effects on human health if escape occurs. The risk from highly toxic compounds is controlled by requiring multiple levels of containment to greatly reduce the probability of escape; whereas compounds that are virtually non-toxic may require little or no containment. The potential for toxicity is determined by the inherent toxicity of the compound and the amount that could potentially escape into the breathing air.

  12. Space Platform

    Microsoft Academic Search

    L. P. Morata; M. W. Novick

    1982-01-01

    The Space Platform (SP) will provide a cost effective long-term host vehicle for scientific and applications payloads beginning in the late 1980's. SP will take advantage of STS capabilities for delivery to orbit, assembly, check-out, maintenance and servicing. Services provided to multiple payloads include electrical power, heat rejection, attitude control and high-rate data handling communications. The system includes self-contained altitude

  13. Space Sciences

    NSDL National Science Digital Library

    2007-12-12

    The latest addition to the Office of Naval Research's Science and Technology Focus site (last mentioned in March 29, 2002 Scout Report) is the Space Sciences Page. The site contains the Observing the Sky link, which has easily read information, photographs, and illustrations on earth rotation, orbit, seasons, observing stars, and more. The Navy and Satellites link describes the Navy's role in launching satellites and how that's accomplished while additional facts can be found on the Naval Research page.

  14. Space Pens

    NASA Technical Reports Server (NTRS)

    1986-01-01

    Fisher's Space Pen was developed for use in gravity free environments. The cartridge, pressurized with nitrogen, seals out air preventing evaporation and oxidation of the ink. Internal pressures force ink outward toward the ball point. A thixotropic ink is used. The pen will operate from minus 50 to plus 45 degrees Fahrenheit, and will withstand atmospheric extremes. It was used both on the Apollo missions and by Soviet Cosmonauts.

  15. Space Nutrition

    NASA Technical Reports Server (NTRS)

    Smith, Scott M.

    2009-01-01

    Optimal nutrition will be critical for crew members who embark on space exploration missions. Nutritional assessment provides an opportunity to ensure that crewmembers begin their missions in optimal nutritional status, to document changes during a mission and, if necessary, to provide intervention to maintain that status throughout the mission, and to assesses changes after landing in order to facilitate the return to their normal status as soon as possible after landing. We report here the findings from our nutritional assessment of astronauts who participated in the International Space Station (ISS) missions, along with flight and ground-based research findings. We also present ongoing and planned nutrition research activities. These studies provide evidence that bone loss, compromised vitamin status, and oxidative damage are the critical nutritional concerns for space travelers. Other nutrient issues exist, including concerns about the stability of nutrients in the food system, which are exposed to longterm storage and radiation during flight. Defining nutrient requirements, and being able to provide and maintain those nutrients on exploration missions, will be critical for maintaining crew member health.

  16. Space propulsion

    NASA Astrophysics Data System (ADS)

    Kazaroff, John M.

    1993-02-01

    Lewis Research Center is developing broad-based new technologies for space chemical engines to satisfy long-term needs of ETO launch vehicles and other vehicles operating in and beyond Earth orbit. Specific objectives are focused on high performance LO2/LH2 engines providing moderate thrusts of 7,5-200 klb. This effort encompasses research related to design analysis and manufacturing processes needed to apply advanced materials to subcomponents, components, and subsystems of space-based systems and related ground-support equipment. High-performance space-based chemical engines face a number of technical challenges. Liquid hydrogen turbopump impellers are often so large that they cannot be machined from a single piece, yet high stress at the vane/shroud interface makes bonding extremely difficult. Tolerances on fillets are critical on large impellers. Advanced materials and fabricating techniques are needed to address these and other issues of interest. Turbopump bearings are needed which can provide reliable, long life operation at high speed and high load with low friction losses. Hydrostatic bearings provide good performance, but transients during pump starts and stops may be an issue because no pressurized fluid is available unless a separate bearing pressurization system is included. Durable materials and/or coatings are needed that can demonstrate low wear in the harsh LO2/LH2 environment. Advanced materials are also needed to improve the lifetime, reliability and performance of other propulsion system elements such as seals and chambers.

  17. An Empirical Determination of the Intergalactic Background Light Using Near-Infrared Deep Galaxy Survey Data Out to 5 Micrometers and the Gamma-Ray Opacity of the Universe

    NASA Technical Reports Server (NTRS)

    Scully, Sean T.; Malkan, Matthew A.; Stecker, Floyd W.

    2014-01-01

    We extend our previous model-independent determination of the intergalactic background light, based purely on galaxy survey data, out to a wavelength of 5 micrometers. Our approach enables us to constrain the range of photon densities, based on the uncertainties from observationally determined luminosity densities and colors. We further determine a 68% confidence upper and lower limit on the opacity of the universe to gamma-rays up to energies of 1.6/(1 + z) terraelectron volts. A comparison of our lower limit redshift-dependent opacity curves to the opacity limits derived from the results of both ground-based air Cerenkov telescope and Fermi-LAT observations of PKS 1424+240 allows us to place a new upper limit on the redshift of this source, independent of IBL modeling.

  18. European Space Agency European Space Exploration

    E-print Network

    Crawford, Ian

    European Space Agency Aurora European Space Exploration Programme EXECUTIVE SUMMARY #12;2 Aurora Programme EXECUTIVE SUMMARY 1. What is Aurora? A European Space Exploration Programme based on a road map economically and politically as a leading world power, it cannot leave space exploration to the other space

  19. Space Policy Perspectives of Young Space Professionals

    Microsoft Academic Search

    W. Marshall

    2002-01-01

    Space policy, particularly international policies on the military and peaceful uses of space, was a main topic of discussion at the Space Generation Forum (SGF), UNISPACE-III. Ideas and recommendations on this topic are being further developed at the Space Generation Summit (SGS), an event at World Space Congress (WSC) that will unite international students and young professionals to develop a

  20. Space Food

    NASA Technical Reports Server (NTRS)

    1994-01-01

    In planning for the long duration Apollo missions, NASA conducted extensive research into space food. One of the techniques developed was freeze drying. Action Products commercialized this technique, concentrating on snack food including the first freeze-dried ice cream. The foods are cooked, quickly frozen and then slowly heated in a vacuum chamber to remove the ice crystals formed by the freezing process. The final product retains 98 percent of its nutrition and weighs only 20 percent of its original weight. Action snacks are sold at museums, NASA facilities and are exported to a number of foreign countries. Sales run to several million dollars annually.

  1. Space Technospheres

    NASA Astrophysics Data System (ADS)

    Vidmachenko, A. P.; Steklov, A. F.; Primak, N. V.

    2000-01-01

    Two main tendencies of making the Solar System habitable are regarding nowadays: (1) making objects of the Solar System habitable; and (2) making the space of the Solar System habitable. We think that it's better to combine them. We should dezine and build settlements ('technospheres') on such objects as asteroids and comets, using their resources. That is, it is necessary to create 'space technospheres' - a long-termed human settlements in the space. To save energy resources it is necessary to use Near-Earth asteroids enriched with water ice (i. e. extinguished comets) with Near-Earth orbits. To realize listed conceptions it is necessary to decrease (up to 100 times) the cost price of the long-termed settlements. That's why even average UN country will be able to create it's own space house - artificial planet ('technosphere') and maintain life activities there. About 50-100 such artificial planets will represent the future civilization of our Solar System. At the same time Earth will stay basic, maternal planet. There is an interesting problem of correcting orbits of that objects. Orbits can be changed into circular or elongated to make them comfortable for living activities of 5000-10000 settlers, and to maintain connection with maternal planet. Technospheres with the elongated orbits are more advantageous to assimilate the Solar System. While technospheres with circular orbits suit to the industrial cycle with certain specialization. The specialization of the technosphere will depend on mine-workings and/or chosen high-technology industrial process. Because it is profitable to convert raw materials at the technosphere and then to transport finished products to the maternal planet. It worth to be mentioned that because of the low gravitation and changed life cycle technosphere settlers, new 'Columb' of the Solar System will transform into new mankind. It will happen though it is difficult to imaging this. Because long ago, when fish left the ocean, they didn't realize that began to transform into Homo Sapiens. Human's departure from the 'cradle' of the mankind - Earth - has the same value in the making new environment habitable.

  2. Space Software

    NASA Technical Reports Server (NTRS)

    1990-01-01

    Xontech, Inc.'s software package, XonVu, simulates the missions of Voyager 1 at Jupiter and Saturn, Voyager 2 at Jupiter, Saturn, Uranus and Neptune, and Giotto in close encounter with Comet Halley. With the program, the user can generate scenes of the planets, moons, stars or Halley's nucleus and tail as seen by Giotto, all graphically reproduced with high accuracy in wireframe representation. Program can be used on a wide range of computers, including PCs. User friendly and interactive, with many options, XonVu can be used by a space novice or a professional astronomer. With a companion user's manual, it sells for $79.

  3. An Evolvable Space Telescope for NASA’s Next UVOIR Flagship Mission

    NASA Astrophysics Data System (ADS)

    Lillie, Charles F.; Breckinridge, James B.; MacEwen, Howard A.; Polidan, Ronald S.; Flannery, Martin; Dailey, Dean

    2015-01-01

    NASA has sponsored several studies to develop conceptual designs for the next UVOIR Flagship mission, including an Advanced Technology Large Space Telescope (ATLAST). These studies concluded that a space observatory launched in ~2030 will require a telescope aperture of 8 to 16 meters to address the most compelling astrophysical questions raised by missions such as HST, Kepler, TESS, JWST and WFIRST as well as the large ground based telescopes that will coming on-line in the next decade. This telescope will be designed to search for the bio-signatures of life in the universe as well as to study the physics of star formation and to unravel the complex interactions between dark matter, galaxies and the intergalactic medium.Unfortunately, telescopes with this aperture will have a long development time with peak funding requirements that will absorb most NASA's Astrophysics budget for many years. To minimize this impact on NASA's budget and to drastically shorten the time between program start and 'first light' for this UVOIR space observatory we have been developing conceptual designs for an Evolvable Space Telescope (EST) that would be assembled on-orbit in three stages, beginning with the launch of a 2 mirror 4 x 12 meter telescope with 2 instruments 5 to 7 years after program start, and then adding mirror segments and instruments ay ~ 5 year intervals to obtain a 12-m filled aperture, and then a 20-m filled aperture telescope. We describe our approach in this presentation.

  4. Cosmic Reionization and Early Star-Forming Galaxies: A Joint Analysis of New Constraints from Planck and Hubble Space Telescope

    E-print Network

    Robertson, Brant E; Furlanetto, Steven R; Dunlop, James S

    2015-01-01

    We discuss new constraints on the epoch of cosmic reionization and test the assumption that most of the ionizing photons responsible arose from high redshift star-forming galaxies. Good progress has been made in charting the end of reionization through spectroscopic studies of z~6-8 QSOs, gamma-ray bursts and galaxies expected to host Lyman-alpha emission. However, the most stringent constraints on its duration have come from the integrated optical depth, tau, of Thomson scattering to the cosmic microwave background. Using the latest data on the abundance and luminosity distribution of distant galaxies from Hubble Space Telescope imaging, we simultaneously match the reduced value tau=0.066 +/- 0.012 recently reported by the Planck collaboration and the evolving neutrality of the intergalactic medium with a reionization history within 6 >10) galaxies. Our analysis strengthens the conclusion that star-forming galaxies dominated the reionization process and has important implications for upcoming 21cm experiment...

  5. Space Science in Action: Space Exploration [Videotape].

    ERIC Educational Resources Information Center

    1999

    In this videotape recording, students learn about the human quest to discover what is out in space. Students see the challenges and benefits of space exploration including the development of rocket science, a look back at the space race, and a history of manned space travel. A special section on the Saturn V rocket gives students insight into the…

  6. Space physiology and medicine

    Microsoft Academic Search

    A. E. Nicogossian; Parker J. F. Jr

    1982-01-01

    The state of knowledge in space physiology and medicine are reviewed. Overviews of manned space flight, the space environment, spaceflight systems and procedures, physiological adaptation to space flight, health maintenance of space crew members, and medical problems of space flight are presented.

  7. Planetary Science Space Physics

    E-print Network

    Mojzsis, Stephen J.

    bring together space science, space technology, and the education of the next generation of space space science with hardware design, development, implementation, mission operations, and data management is almost one-of-a-kind among university-based space centers. With up to a dozen space science flight

  8. National Aeronautics and Space Administration NASAGoddardSpaceFlightCenter

    E-print Network

    Christian, Eric

    National Aeronautics and Space Administration NASAGoddardSpaceFlightCenter http Space Flight Center's IPP Office #12;National Aeronautics and Space Administration NASAGoddardSpace SUA=Software Usage Agreement #12;National Aeronautics and Space Administration NASAGoddardSpace

  9. "Space, the Final Frontier"; Books on Space and Space Exploration.

    ERIC Educational Resources Information Center

    Jordan, Anne Devereaux

    1997-01-01

    Advocates play in a child's life. Describes how science fiction seizes the imaginations of young readers with its tales of the future and of outer space. Talks about various nonfiction books about space. Elaborates a workshop on books about space exploration. Gives 10 questions about stimulating student response. (PA)

  10. Space on Earth.

    ERIC Educational Resources Information Center

    Leder, Sandra J.

    1992-01-01

    Describes ideas for applying research from space programs to life science instruction including plants in space, exercise and diet on space flights, environmental advantages from space exploration, and the effects of microgravity on health. Discusses space spinoffs used in medicine including digital imaging processing and the Ingestible Thermal…

  11. Space Science and Marshall Space Flight Center

    NASA Technical Reports Server (NTRS)

    Spann, James

    2005-01-01

    Space Science a t Marshall Space Flight Center is diverse and very interesting. It ranges from high energy astrophysics to astrobiology, from solar physics to space weather to dusty plasmas. I will present some of the more interesting investigations regarding auroral physics, what it takes to build a space camera, and laboratory investigations of dust. There will be time for questions and answers at the conclusion.

  12. SpaceTech—Postgraduate space education

    Microsoft Academic Search

    Ferdi J. de Bruijn; Edward W. Ashford; Wiley J. Larson

    2008-01-01

    SpaceTech is a postgraduate program geared primarily for mid-career space professionals seeking to gain or improve their expertise in space systems engineering and in business engineering. SpaceTech provides a lifelong impact on its participants by broadening their capabilities, encouraging systematic “end-to-end” thinking and preparing them for any technical or business-related engineering challenges they may encounter. This flexible 1-year program offers

  13. Space history, space policy, and executive leadership

    NASA Technical Reports Server (NTRS)

    Kraemer, Sylvia K.

    1993-01-01

    A lecture that attempts to establish the role of space historians in formulating space policy is presented. The discussion focusses on two adages and their relevance to space policy. The adages are as follows: 'write about what you know;' and 'good managers do things right; good executives do the right things.'

  14. NASA Space Shuttle Processing

    NASA Technical Reports Server (NTRS)

    Andruske, Linda Lee

    2010-01-01

    This viewgraph presentation reviews NASA's Space Shuttle Processing at Kennedy Space Center. A demonstration of the Space Shuttle silica tiles, a description of its High Temperature Reusable Surface Insulation (HRSI), tile inspections, and tile replacement demonstrations are also presented.

  15. Sculpting space through sound

    E-print Network

    Nakagawa, Junko, 1975-

    2002-01-01

    How does one experience space? What kind of information do humans collect in the process of constructing space in their mind? How does one begin to understand volume, light, texture, material, smell and sense of space? The ...

  16. Space Solar Power Program

    SciTech Connect

    Arif, H.; Barbosa, H.; Bardet, C.; Baroud, M.; Behar, A.; Berrier, K.; Berthe, P.; Bertrand, R.; Bibyk, I.; Bisson, J.; Bloch, L.; Bobadilla, G.; Bourque, D.; Bush, L.; Carandang, R.; Chiku, T.; Crosby, N.; De Seixas, M.; De Vries, J.; Doll, S.; Dufour, F.; Eckart, P.; Fahey, M.; Fenot, F.; Foeckersperger, S.; Fontaine, J.E.; Fowler, R.; Frey, H.; Fujio, H.; Gasa, J.M.; Gleave, J.; Godoe, J.; Green, I.; Haeberli, R.; Hanada, T.; Ha

    1992-08-01

    Information pertaining to the Space Solar Power Program is presented on energy analysis; markets; overall development plan; organizational plan; environmental and safety issues; power systems; space transportation; space manufacturing, construction, operations; design examples; and finance.

  17. The International Space Station in Space Exploration

    NASA Technical Reports Server (NTRS)

    Gerstenmaier, William H.; McKay, Meredith M.

    2006-01-01

    The International Space Station (ISS) Program has many lessons to offer for the future of space exploration. Among these lessons of the ISS Program, three stand out as instrumental for the next generation of explorers. These include: 1) resourcefulness and the value of a strong international partnership; 2) flexibility as illustrated by the evolution of the ISS Program and 3) designing with dissimilar redundancy and simplicity of sparing. These lessons graphically demonstrate that the ISS Program can serve as a test bed for future programs. As the ISS Program builds upon the strong foundation of previous space programs, it can provide insight into the prospects for continued growth and cooperation in space exploration. As the capacity for spacefaring increases worldwide and as more nations invest in space exploration and space sector development, the potential for advancement in space exploration is unlimited. By building on its engineering and research achievements and international cooperation, the ISS Program is inspiring tomorrow s explorers today.

  18. On the Critical Ionization Velocity Effect in Interstellar Space and Possible Detection of Related Continuum Emission

    E-print Network

    Gerrit L. Verschuur

    2007-04-23

    Interstellar neutral hydrogen (HI) emission spectra manifest several families of linewidths whose numerical values (34, 13 & 6 km/s) appear to be related to the critical ionization velocities (CIVs) of the most abundant interstellar atomic species. Extended new analysis of HI emission profiles shows that the 34 km/s wide component, probably corresponding to the CIV for helium, is pervasive. The 34 km/s wide linewidth family is found in low-velocity (local) neutral hydrogen (HI) profiles as well as in the so-called high-velocity clouds. In addition, published studies of HI linewidths found in the Magellanic Stream, Very-High-Velocity Clouds, and Compact High-Velocity Clouds, all of which are believed to be intergalactic, have noted that typical values are of the same order. If the critical ionization velocity effect does play a role in interstellar space it may be expected to produce locally enhanced electron densities where rapidly moving neutral gas masses interact with surrounding plasma. Evidence is presented that suggests that this phenomenon is occurring in interstellar space. It manifests as a spatial association between peaks in HI structure offset with respect to peaks in high-frequency radio continuum data obtained with the Wilkinson Microwave Anisotropy Probe.

  19. Studying Galaxy Formation and Reionization with the James Webb Space Telescope

    NASA Technical Reports Server (NTRS)

    Gardner, Jonathan P.

    2008-01-01

    The deepest optical to infrared observations of the universe include the Hubble Deep Fields, the Great Observatories Origins Deep Survey and the recent Hubble Ultra-Deep Field. Galaxies are seen in these surveys at redshifts z>6, less than 1 Gyr after the Big Bang, at the end of a period when light from the galaxies has reionized Hydrogen in the inter-galactic medium. These observations, combined with theoretical understanding, indicate that the first stars and galaxies formed at z>10, beyond the reach of the Hubble and Spitzer Space Telescopes. To observe the first galaxies, NASA is planning the James Webb Space Telescope (JWST), a large (6.5m), cold (<50K), infrared-optimized observatory to be launched early in the next decade into orbit around the second Earth- Sun Lagrange point. JWST will have four instruments: The Near-Infrared Camera, the Near-Infrared multi-object Spectrograph, and the Tunable Filter Imager will cover the wavelength range 0.6 to 5 microns, while the Mid-Infrared Instrument will do both imaging and spectroscopy from 5 to 28.5 microns. I will review the current status of the project.

  20. 8 Meter Advanced Technology Large-Aperture Space Telescope (ATLAST-8m)

    NASA Technical Reports Server (NTRS)

    Stahl, H. Philip

    2010-01-01

    ATLAST-8m (Advanced Technology Large Aperture Space Telescope) is a proposed 8-meter monolithic UV/optical/NIR space observatory (wavelength range 110 to 2500 nm) to be placed in orbit at Sun-Earth L2 by NASA's planned Ares V heavy lift vehicle. Given its very high angular resolution (15 mas @ 500 nm), sensitivity and performance stability, ATLAST-8m is capable of achieving breakthroughs in a broad range of astrophysics including: Is there life elsewhere in the Galaxy? An 8-meter UVOIR observatory has the performance required to detect habitability (H2O, atmospheric column density) and biosignatures (O2, O3, CH4) in terrestrial exoplanet atmospheres, to reveal the underlying physics that drives star formation, and to trace the complex interactions between dark matter, galaxies, and intergalactic medium. The ATLAST Astrophysics Strategic Mission Concept Study developed a detailed point design for an 8-m monolithic observatory including optical design; structural design/analysis including primary mirror support structure, sun shade and secondary mirror support structure; thermal analysis; spacecraft including structure, propulsion, GN&C, avionics, power systems and reaction wheels; mass and power budgets; and system cost. The results of which were submitted by invitation to NRC's 2010 Astronomy & Astrophysics Decadal Survey.

  1. Space Toxicology: Human Health during Space Operations

    NASA Technical Reports Server (NTRS)

    Khan-Mayberry, Noreen; James, John T.; Tyl, ROchelle; Lam, Chiu-Wing

    2010-01-01

    Space Toxicology is a unique and targeted discipline for spaceflight, space habitation and occupation of celestial bodies including planets, moons and asteroids. Astronaut explorers face distinctive health challenges and limited resources for rescue and medical care during space operation. A central goal of space toxicology is to protect the health of the astronaut by assessing potential chemical exposures during spaceflight and setting safe limits that will protect the astronaut against chemical exposures, in a physiologically altered state. In order to maintain sustained occupation in space on the International Space Station (ISS), toxicological risks must be assessed and managed within the context of isolation continuous exposures, reuse of air and water, limited rescue options, and the need to use highly toxic compounds for propulsion. As we begin to explore other celestial bodies in situ toxicological risks, such as inhalation of reactive mineral dusts, must also be managed.

  2. Space: The New Frontier.

    ERIC Educational Resources Information Center

    National Aeronautics and Space Administration, Washington, DC.

    This document is designed primarily to describe the U.S. Space Program, its history, its current state of development, and its goals for the future. Chapter headings include: Space and You; The Early History of Space Flight; The Solar System; Space Probes and Satellites; Scientific Satellites and Sounding Rockets; Application Satellites, Unmanned…

  3. Organic chemistry in space

    NASA Technical Reports Server (NTRS)

    Johnson, R. D.

    1977-01-01

    Organic cosmochemistry, organic materials in space exploration, and biochemistry of man in space are briefly surveyed. A model of Jupiter's atmosphere is considered, and the search for organic molecules in the solar system and in interstellar space is discussed. Materials and analytical techniques relevant to space exploration are indicated, and the blood and urine analyses performed on Skylab are described.

  4. SPACE SYSTEMS ENGINEERING

    E-print Network

    Yang, Eui-Hyeok

    , the leading educational institute for technical mission analysis and design, and the International Space to design cutting edge space missions, systems and associated products, as well as the systems knowledge0213 SPACE SYSTEMS ENGINEERING In today's space community, change is the only constant. From market

  5. Space Guidelines for Libraries.

    ERIC Educational Resources Information Center

    Wisconsin Coordinating Committee for Higher Education, Madison.

    The following guidelines are recommended: stack space--for each 10 volumes, one square foot of space; reading room--25 square feet per station x 20% of the total undergraduate population; carrel space--25% of the graduate enrollment x 45 square feet; office and auxilliary space--135 square feet x full time equivalent staff. (NI)

  6. China's Space Policy

    Microsoft Academic Search

    Y. Wen

    2002-01-01

    The scope of mankind's explorations has expanded from the land to the ocean, from the ocean to the air and from the air to outer space. Space technology, which emerged in the 1950's, opened up a new era of human exploration of outer space. Having developed rapidly for the last half century, mankind's activities in space have come a long

  7. Achievements in space robotics

    Microsoft Academic Search

    Kazuya Yoshida

    2009-01-01

    Outer space is an ultimate field for the application of robotics technology. As outer space is a harsh environment with extreme temperatures, vacuum, radiation, gravity, and great distances, human access is very difficult and hazardous and is therefore limited. To assist human activities in space for constructing and maintaining space modules and structures, robotic manipulators have been playing essential roles

  8. Using space resources

    NASA Astrophysics Data System (ADS)

    Sullivan, Thomas A.; McKay, David S.

    1991-10-01

    The topics covered include the following: reducing the cost of space exploration; the high cost of shipping; lunar raw materials; some useful space products; energy from the moon; ceramic, glass, and concrete construction materials; mars atmosphere resources; relationship to the Space Exploration Initiative (SEI); an evolutionary approach to using space resources; technology development; and oxygen and metal coproduction.

  9. Bioprocessing in Space

    NASA Technical Reports Server (NTRS)

    Morrison, D. R. (compiler)

    1977-01-01

    Proceedings are presented of the 1976 NASA Colloquium on bioprocessing in space. The program included general sessions and formal presentations on the following topics: NASA's Space Shuttle, Spacelab, and space-processing programs; the known unusual behavior of materials in space; space-processing experiment results; cell biology, gravity sensors in cells, space electrophoresis of living cells, new approaches to biosynthesis of biologicals from cell culture in space, and zero-g fermentation concepts; and upcoming flight opportunities and industrial application planning studies already underway.

  10. Space Science Curricula

    NASA Technical Reports Server (NTRS)

    1990-01-01

    Johnson High School, Huntsville, Alabama started an international magnet program in 1987. One of the courses in the curriculum was in space science. They appealed to Marshall Space Flight Center (MSFC) when they couldn't find a suitable textbook, nor locate other classes in space science to provide a guideline. MSFC agreed to help and placed the school under an official 'Adopt-A-School' program. MSFC's chief scientist and others at the space center helped prepare a very comprehensive space science program. Examples of the subjects covered include problems of space travel, materials processing in space, technology utilization, robotics, space colonization, etc. MSFC followed up by working with Johnson High to determine if the curriculum is generally usable and workable. If it is, MSFC may make it available to other schools. MSFC not only developed the space science curriculum; they continue to support the program by sponsoring hands- on activities and tours of space research facilities.

  11. Space Physiology and Operational Space Medicine

    NASA Technical Reports Server (NTRS)

    Scheuring, Richard A.

    2009-01-01

    The objectives of this slide presentation are to teach a level of familiarity with: the effects of short and long duration space flight on the human body, the major medical concerns regarding future long duration missions, the environmental issues that have potential medical impact on the crew, the role and capabilities of the Space Medicine Flight Surgeon and the environmental impacts experienced by the Apollo crews. The main physiological effects of space flight on the human body reviewed in this presentation are: space motion sickness (SMS), neurovestibular, cardiovascular, musculoskeletal, immune/hematopoietic system and behavioral/psycho-social. Some countermeasures are discussed to these effects.

  12. Space Today Online

    NSDL National Science Digital Library

    Anthony R. Curtis, Ph.D.

    2006-03-07

    This online magazine is intended to provide accurate information on past, present, and future human activities in and about space, including space science, history, research, space flight, solar system exploration, deep space astronomy, and cosmology. It features news articles on space vehicles, astronauts, coming launches and landings, satellite missions, telescopes, and many other topics. The site also provides image galleries, videos, and resources for teachers such as lesson plans, book reviews, tutorials, and other items.

  13. Noncommutative spherically symmetric spaces

    SciTech Connect

    Murray, Sean; Govaerts, Jan [Centre for Cosmology, Particle Physics and Phenomenology, Universite catholique de Louvain, Chemin du Cyclotron 2, B-1348 Louvain-la-Neuve (Belgium); Centre for Cosmology, Particle Physics and Phenomenology, Universite catholique de Louvain, Chemin du Cyclotron 2, B-1348 Louvain-la-Neuve (Belgium) and International Chair in Mathematical Physics and Applications, University of Abomey-Calavi, 072 B. P. 50, Cotonou (Benin)

    2011-01-15

    We examine some noncommutative spherically symmetric spaces in three space dimensions. A generalization of Snyder's noncommutative (Euclidean) space allows the inclusion of the generator of dilations into the defining algebra of the coordinate and rotation operators. We then construct a spherically symmetric noncommutative Laplacian on this space having the correct limiting spectrum. This is presented via a creation and annihilation operator realization of the algebra, which may lend itself to a truncation of the Hilbert space.

  14. Space Shuttle Familiarization

    NASA Technical Reports Server (NTRS)

    Mellett, Kevin

    2006-01-01

    This slide presentation visualizes the NASA space center and research facility sites, as well as the geography, launching sites, launching pads, rocket launching, pre-flight activities, and space shuttle ground operations located at NASA Kennedy Space Center. Additionally, highlights the international involvement behind the International Space Station and the space station mobile servicing system. Extraterrestrial landings, surface habitats and habitation systems, outposts, extravehicular activity, and spacecraft rendezvous with the Earth return vehicle are also covered.

  15. Redshift-space distortion of the 21-cm background from the epoch of reionization - I. Methodology re-examined

    NASA Astrophysics Data System (ADS)

    Mao, Yi; Shapiro, Paul R.; Mellema, Garrelt; Iliev, Ilian T.; Koda, Jun; Ahn, Kyungjin

    2012-05-01

    The peculiar velocity of the intergalactic gas responsible for the cosmic 21-cm background from the epoch of reionization and beyond introduces an anisotropy in the three-dimensional power spectrum of brightness temperature fluctuations. Measurement of this anisotropy by future 21-cm surveys is a promising tool for separating cosmology from 21-cm astrophysics. However, previous attempts to model the signal have often neglected peculiar velocity or only approximated it crudely. This paper re-examines the effects of peculiar velocity on the 21-cm signal in detail, improving upon past treatment and addressing several issues for the first time. (1) We show that even the angle-averaged power spectrum, P(k), is affected significantly by the peculiar velocity. (2) We re-derive the brightness temperature dependence on atomic hydrogen density, spin temperature, peculiar velocity and its gradient and redshift to clarify the roles of thermal versus velocity broadening and finite optical depth. (3) We show that properly accounting for finite optical depth eliminates the unphysical divergence of the 21-cm brightness temperature in overdense regions of the intergalactic medium found by previous work that employed the usual optically thin approximation. (4) We find that the approximation made previously to circumvent the diverging brightness temperature problem by capping the velocity gradient can misestimate the power spectrum on all scales. (5) We further show that the observed power spectrum in redshift space remains finite even in the optically thin approximation if one properly accounts for the redshift-space distortion. However, results that take full account of finite optical depth show that this approximation is only accurate in the limit of high spin temperature. (6) We also show that the linear theory for redshift-space distortion widely employed to predict the 21-cm power spectrum results in a ˜30 per cent error in the observationally relevant wavenumber range k˜ 0.1-1 h Mpc-1, when strong ionization fluctuations exist (e.g. at the 50 per cent ionized epoch). We derive an alternative, quasi-linear formulation which improves upon the accuracy of the linear theory. (7) We describe and test two numerical schemes to calculate the 21-cm signal from reionization simulations to incorporate peculiar velocity effects in the optically thin approximation accurately, by real- to redshift-space re-mapping of the H I density. One is particle based, the other grid based, and while the former is most accurate, we demonstrate that the latter is computationally more efficient and can be optimized so as to achieve sufficient accuracy.

  16. National Aeronautics and Space Administration Commercial Space Committee

    E-print Network

    Waliser, Duane E.

    National Aeronautics and Space Administration Commercial Space Committee of the NASA Advisory ______________________________________________ John Emond, Executive Secretary Commercial Space Committee _____________________________________________ Bretton Alexander, Chair Commercial Space Committee #12;NAC Commercial Space Committee, July 29, 2010

  17. National Aeronautics and Space Administration Commercial Space Committee

    E-print Network

    Waliser, Duane E.

    National Aeronautics and Space Administration Commercial Space Committee of the NASA Advisory space transportation Will Trafton, formerly NASA associate Administrator for space flight, executive Commercial Space Committee, February 16, 2010 4 Committee Direction NASA's Deputy Administrator, Ms Lori

  18. SPACE FOR INNOVATION (OR INNOVATION FOR SPACE)

    E-print Network

    Karlsson, Brynjar

    ­ Push new technology on missions ­ Pull solutions for missions from researchers ­ Successful approach at NASA ­ Lessons from Silicon Valley · Space for innovation ­ Opportunities in Iceland · Space for innovation v. 2.0 ­ Environment for innovation #12;www.hr.is Driving Innovation at NASA · The need

  19. SpaceTech—Postgraduate space education

    NASA Astrophysics Data System (ADS)

    de Bruijn, Ferdi J.; Ashford, Edward W.; Larson, Wiley J.

    2008-07-01

    SpaceTech is a postgraduate program geared primarily for mid-career space professionals seeking to gain or improve their expertise in space systems engineering and in business engineering. SpaceTech provides a lifelong impact on its participants by broadening their capabilities, encouraging systematic "end-to-end" thinking and preparing them for any technical or business-related engineering challenges they may encounter. This flexible 1-year program offers high competency gain and increased business skills. It is held in attractive locations in a flexible, multi-cultural environment. SpaceTech is a highly effective master's program certified by the esteemed Technical University of Delft (TUD), Netherlands. SpaceTech provides expert instructors who place no barriers between themselves and participants. The program combines innovative and flexible new approaches with time-tested methods to give participants the skills required for future missions and new business, while allowing participants to meet their work commitments at the same time as they study for their master's degree. The SpaceTech program is conducted in separate sessions, generally each of 2-week duration, separated by periods of some 6-8 weeks, during which time participants may return to their normal jobs. It also includes introductory online course material that the participants can study at their leisure. The first session is held at the TUD, with subsequent sessions held at strategic space agency locations. By participating at two or more of these sessions, attendees can earn certificates of satisfactory completion from TU Delft. By participating in all of the sessions, as well as taking part in the companion Central Case Project (CCP), participants earn an accredited and highly respected master's degree in Space Systems Engineering from the TUD. Seven distinct SpaceTech modules are provided during these sessions: Space Mission Analysis and Design, Systems Engineering, Business Engineering, Interpersonal Skills, Telecommunications, Earth Observation and Navigation. A group CCP, a major asset of this unique program, is a focused project, aimed at the formation of a credible virtual commercial space-related business. Participants exercise space systems engineering fundamentals as well as marketing and business engineering tools, with the goal of creating a financially viable business opportunity. They then present the result, in the form of an unsolicited proposal to potential investors, as well as a varied group of engineers, managers and executives from the space community. During the CCP, participants learn the ties between mission and system design and the potential return to investors. They develop an instinct for the technical concepts and which of the parameters to adjust to make their newly conceived business more effective and profitable.

  20. Section 2: The Space of Media Space

    NASA Astrophysics Data System (ADS)

    Harrison, Steve

    We began our study of media space with the social aspects of mediated communication because many in the computer-supported cooperative work (CSCW) realm are familiar with models, theories, frameworks, issues, and design approaches related to sociality. But the first media space research came from another set of traditions — the ordering of space and the making of place. Formally, these are the professional and intellectual provinces of architecture, which are probably remote from the disciplinary backgrounds of most readers. However, remoteness in terms of rhetoric and training does not prevent proximity to everyday human experience. The meaning of media space with respect to human experience is the focus of the articles in this section. The spaces are designed to have meaning, and the meaning of the design derives from spatial experience.

  1. Space Station Spartan study

    NASA Technical Reports Server (NTRS)

    Lane, J. H.; Schulman, J. R.; Neupert, W. M.

    1985-01-01

    The required extension, enhancement, and upgrading of the present Spartan concept are described to conduct operations from the space station using the station's unique facilities and operational features. The space station Spartan (3S), the free flyer will be deployed from and returned to the space station and will conduct scientific missions of much longer duration than possible with the current Spartan. The potential benefits of a space station Spartan are enumerated. The objectives of the study are: (1) to develop a credible concept for a space station Spartan; and (2) to determine the associated requirements and interfaces with the space station to help ensure that the 3S can be properly accommodated.

  2. National Aeronautics and Space Administration

    E-print Network

    Christian, Eric

    Edwards, CA Johnson Space Center Houston, TX Stennis Space Center SSC, MS Kennedy Space Center KSC, FL of Inspector General Mail Stop KSC/OIG John F. Kennedy Space Center Kennedy Space Center, FL 32815-0001 Tel

  3. Space transportation, satellite services, and space platforms

    NASA Technical Reports Server (NTRS)

    Disher, J. H.

    1979-01-01

    The paper takes a preview of the progressive development of vehicles for space transportation, satellite services, and orbital platforms. A low-thrust upper stage of either the ion engine or chemical type will be developed to transport large spacecraft and space platforms to and from GEO. The multimission spacecraft, space telescope, and other scientific platforms will require orbital serves going beyond that provided by the Shuttle's remote manipulator system, and plans call for extravehicular activity tools, improved remote manipulators, and a remote manned work station (the cherry picker).

  4. astronautics & space technology

    E-print Network

    Rohs, Remo

    , space environment, attitude determination and control, telecom- munications, propulsion, structures and mecha- nisms, thermal control, power systems, launch systems and facilities. (Duplicates credit28 astronautics & space technology aste overview · programs available courses of instruction

  5. French space activities

    NASA Technical Reports Server (NTRS)

    Blanc, R.

    1982-01-01

    The four main points of research and development of space programs by France are explained. The National Center of Space Studies is discussed, listing the missions of the Center and describing the activities of the staff.

  6. European Space Agency (ESA)

    NASA Astrophysics Data System (ADS)

    Murdin, P.

    2000-11-01

    An international organization whose task is `to provide for and to promote, for exclusively peaceful purposes, cooperation among European states in space research and technology and their space applications'....

  7. Space Glasgow Executive Summary

    E-print Network

    Glasgow, University of

    to wide-ranging and high quality space research, and the Space Glasgow Research Cluster has been funding sources, both public and private, amounting to a current portfolio of around £14 million. Working

  8. Causal Learning Space Carving

    E-print Network

    Ghahramani, Zoubin

    Causal Learning Space Carving Deep CRFs Cambridge Interview Technical Talk David Duvenaud February 2, 2010 David Duvenaud Cambridge Interview Technical Talk #12;Causal Learning Space Carving Deep Results 3 Deep CRFs Motivation Recursive Segmentation Learning David Duvenaud Cambridge Interview

  9. Pathfinder: Humans in space

    NASA Technical Reports Server (NTRS)

    Anderson, John L.

    1988-01-01

    Viewgraphs are presented on the Pathfinder program. Information is given on human exploration of the solar system, technical requirements interfaces, program objectives, space suits, human performance, man-machine systems, space habitats, life support systems, and artificial gravity

  10. The Classroom Space Project.

    ERIC Educational Resources Information Center

    Verbickas, Sarah

    2002-01-01

    Introduces the Classroom Space project aimed at revitalizing science education at Key Stages 3 and 4 by using exciting examples from Space Science and Astronomy to illustrate key science concepts. (Author/YDS)

  11. Space Radiation Program Element

    NASA Technical Reports Server (NTRS)

    Krenek, Sam

    2008-01-01

    This poster presentation shows the various elements of the Space Radiation Program. It reviews the program requirements: develop and validate standards, quantify space radiation human health risks, mitigate risks through countermeasures and technologies, and treat and monitor unmitigated risks.

  12. Dosimetry of space radiations

    NASA Technical Reports Server (NTRS)

    Arkhangelskiy, V. V.; Markelov, V. V.; Skvortsov, S. S.; Smirennyy, L. N.; Turkin, V. N.; Chernykh, I. V.

    1973-01-01

    Harmful effects of space radiation are discussed. Radiation dosimetry methods are given. Dosimetry monitoring is investigated. Methods for measuring space radiation by ionization, thermoluminescence, and nuclear photographic emulsions are described.

  13. Welding in Space Workshop

    NASA Technical Reports Server (NTRS)

    Workman, Gary L.

    1990-01-01

    The potential was discussed for welding in space, its advantages and disadvantages, and what type of programs can benefit from the capability. Review of the various presentations and comments made in the course of the workshop suggests several routes to obtaining a better understanding of how welding processes can be used in NASA's initiatives in space. They are as follows: (1) development of a document identifying well processes and equipment requirements applicable to space and lunar environments; (2) more demonstrations of welding particular hardware which are to be used in the above environments, especially for space repair operations; (3) increased awareness among contractors responsible for building space equipment as to the potential for welding operations in space and on other planetary bodies; and (4) continuation of space welding research projects is important to maintain awareness within NASA that welding in space is viable and beneficial.

  14. Earth and Space

    NSDL National Science Digital Library

    2014-09-18

    In earth and space science, students study the origin, structure, and physical phenomena of the earth and the universe. Earth and space science studies include concepts in geology, meteorology, oceanography, and astronomy.

  15. Space solar cell research

    NASA Technical Reports Server (NTRS)

    Flood, Dennis J.

    1989-01-01

    A brief overview is given of the scope of the NASA space solar cell research and development program. Silicon cells, gallium arsenide cells, indium phosphide cells, and superlattice solar cells are addressed, indicating the state of the art of each type in outer space and their advantages and drawbacks for use in outer space. Contrasts between efficiency in space and on earth are pointed out.

  16. Clinical Space Medicine Panel

    NASA Technical Reports Server (NTRS)

    Baisden, Denise L.; Billica, Roger (Technical Monitor)

    2000-01-01

    The practice of space medicine is diverse. It includes routine preventive medical care of astronauts and pilots, the development of inflight medical capability and training of flight crews as well as the preflight, inflight, and postflight medical assessment and monitoring. The Johnson Space Center Medical Operations Branch is a leader in the practice of space medicine. The papers presented in this panel will demonstrate some of the unique aspects of space medicine.

  17. Normal, Not Paracompact Spaces

    E-print Network

    Fleissner, William G.

    1982-07-01

    BULLETIN (New Series) OF THE AMERICAN MATHEMATICAL SOCIETY Volume 7, Number 1, July 1982 NORMAL, NOT PARACOMPACT SPACES BY WILLIAM G. FLEISSNER1 ABSTRACT. We describe some recently constructed counterexamples in general topology, including a... normal, nonmetrizable Moore space, a normal para-Lindelof, not paracompact space, and a normal, screenable, not paracompact space. The period 1948—1952, when the notions of paracompactness and metrizabil- ity were investigated in terms of discrete...

  18. US space commerce, 1991

    NASA Technical Reports Server (NTRS)

    Pace, Scott

    1992-01-01

    The topics are presented in viewgraph form and include the following: the US share of commercial payloads in comparison with Ariane's share; world communications satellite orders; the US share of prime contracts for construction of commercial communications satellites; emerging markets; space activities at the Commerce Department (DOC); Office of Space Commerce (OSC) mission description; key drivers for commercial space; and general DOC space policy themes.

  19. Animals in space

    NASA Technical Reports Server (NTRS)

    White, Angela

    1988-01-01

    Animals are indispensable to the space program. Their continued use could have many significant results. Those who are opposed to using animals in space should remember that space animals are treated humanely; they are necessary because results can be obtained from them that would be unobtainable from humans; and results from animal experiments can be applied to human systems. Therefore, NASA should continue to use animals in space research.

  20. Ice in Space

    NSDL National Science Digital Library

    This is a detailed lesson about space and how Earth fits in it. Learners will consider the essential question, "What is space?" Activities include small group miming, speaking, drawing, and/or writing about space and the evidence for ice in space. Included are detailed games and dialogue. Native stories are shared. This is lesson 9 of 12 in the unit, Exploring Ice in the Solar System.

  1. Access to space: The Space Shuttle's evolving rolee

    Microsoft Academic Search

    Steven R. Duttry

    1993-01-01

    Access to space is of extreme importance to our nation and the world. Military, civil, and commercial space activities all depend on reliable space transportation systems for access to space at a reasonable cost. The Space Transportation System or Space Shuttle was originally planned to provide transportation to and from a manned Earth-orbiting space station. To justify the development and

  2. The Ninth National Space Symposium

    NASA Astrophysics Data System (ADS)

    Lipskin, Beth Ann; Patterson, Sara; Brescia, David A.; Burk, Donna; Flannery, Jack; St. John, Pat; Zimkas, Chuck

    Proceedings of the Ninth National Space Symposium held 13-16 April 1993 by the United States Space Foundation are presented. Presentations made at the symposium are included. Topics discussed include: Change, Challenge and Opportunity; Washington Insiders: National Space Policy and Budget Issues; Civil Space: a Vision for the Future; Space Power for an Expanded Vision; Unparalled Launch Vehicle Propulsion Capabilities; National Security Space Issues; Perspectives on the Air Force in Space; Future Technology: Space Propulsion, Earth Observation and International Cooperation; Achieving Efficient Space Transportation; the Future in Space Exploration; Kids, Parents and Teachers are into Space; and Public Congressional Forum on Space - International Space Issues.

  3. Deep Space Telecommunications

    NASA Technical Reports Server (NTRS)

    Kuiper, T. B. H.; Resch, G. M.

    2000-01-01

    The increasing load on NASA's deep Space Network, the new capabilities for deep space missions inherent in a next-generation radio telescope, and the potential of new telescope technology for reducing construction and operation costs suggest a natural marriage between radio astronomy and deep space telecommunications in developing advanced radio telescope concepts.

  4. Space Weather Now

    NSDL National Science Digital Library

    Space Environment Center

    The Space Weather Now page is intended to give the non-technical user a "plain language" look at space weather. It includes information about relevant events and announcements, data from and about different instruments and satellites watching various aspects of space weather, alerts and advisories, daily themes of products and services, and links appropriate for the various groups of users.

  5. United States Space Policy

    E-print Network

    Colorado at Boulder, University of

    to consider the effects of U.S. export reg- ulations on the country's commercial space industry. Abbey the commercial space industry but also potentially the workforce on which it depended. The national security a long-term balance of commercial, military, and scientific activities in space. The project is producing

  6. Space processing applications bibliography

    NASA Technical Reports Server (NTRS)

    1978-01-01

    This special bibliography lists 724 articles, papers, and reports which discuss various aspects of the use of the space environment for materials science research or for commercial enterprise. The potentialities of space processing and the improved materials processes that are made possible by the unique aspects of the space environment are emphasized. References identified in April, 1978 are cited.

  7. Space Photography 1977 Index

    NASA Technical Reports Server (NTRS)

    1976-01-01

    An index is provided to representative photographs and transparencies available from NASA. Subjects include spacecraft, astronauts, lunar surface, planets and outer space phenomena, earth observations, and aviation. High altitude aircraft infrared photographs are included along with artists' conceptions of space shuttle and space colonies.

  8. Marshall Space Flight Center

    NASA Astrophysics Data System (ADS)

    Murdin, P.

    2000-11-01

    NASA's George C Marshall Space Flight Center is located in Huntsville, Alabama. It is the agency's leading center for space transportation and propulsion development. The Saturn launch vehicles used in the Apollo Moon program were designed and developed here. Today, it provides the solid rocket boosters, main engines and external tank for the Space Shuttle. Apart from upgrades to these systems, M...

  9. Brazilian Space Weather Program

    Microsoft Academic Search

    Antonio Padilha; Hisao Takahashi; Eurico de Paula; Hanumant Sawant; Haroldo de Campos Velho; Icaro Vitorello; Joaquim Costa; Jonas Souza; José Cecatto; Odim Mendes; Walter Demétrio Gonzalez Alarcon

    2008-01-01

    A space weather program is being initiated at the Brazilian National Institute for Space Research (INPE) to study events from their initiation on the sun to their impacts on the earth, including their effects on space-based and ground-based technological systems. The program is built on existing capabilities at INPE, which include scientists with a long tradition and excellence in the

  10. Prototype space fabrication platform

    Microsoft Academic Search

    James A. Bessel; James M. Ceney; David M. Crean; Edward A. Ingham; David J. Pabst

    1993-01-01

    Current plans for constructing large structures in space entail fabricating the primary components, such as truss segments, on the ground and assembling them in space. This process requires an exorbitant number of support missions, and methods to minimize the number must be considered. Whenever the space shuttle is launched, its external tank is jettisoned and destroyed prior to reaching orbit.

  11. Space travel and gravity

    Microsoft Academic Search

    P. Karmakar; Greeninavin

    2010-01-01

    Space travelling is not possible for human because, by the time, we cross Jupiter, our bones dissolve as there is zero gravity and, by developing a gravity chamber in the space ship itself we will be able to travel in space for generations and explore the universe.

  12. Augmented collaborative spaces

    Microsoft Academic Search

    Gopal Pingali; Noi Sukaviriya

    2003-01-01

    As collaborative environments evolve beyond the desktop, we see the emergence of a new class of augmented collaborative spaces that employ various devices and technologies to merge electronic information with physical space to support collaboration, both local and remote. To be effective, such spaces should give people the flexibility to combine their individual resources with the resources available in the

  13. Radiation effects in space

    SciTech Connect

    Fry, R.J.M.

    1987-07-01

    As more people spend more time in space, and the return to the moon and exploratory missions are considered, the risks require continuing examination. The effects of microgravity and radiation are two potential risks in space. These risks increase with increasing mission duration. This document considers the risk of radiation effects in space workers and explorers. 17 refs., 1 fig., 4 tabs.

  14. Space Station - early

    NASA Technical Reports Server (NTRS)

    1962-01-01

    James Hansen wrote: 'Langley engineers check out the interior of the inflatable 24-foot space station in January 1962.'... 'The first idea for an inflatable station was the Erectable Torus Manned Space Laboratory. A Langley space station team led by Paul Hill and Emanuel 'Manny' Schnitzer developed the concept with the help of the Goodyear Aircraft Corporation.'

  15. Deep space optical communications

    NASA Astrophysics Data System (ADS)

    Sokoloski, Martin M.; Lesh, James R.

    1987-01-01

    Preliminary concepts and designs of a deep space optical link for planetary and deep space science are described. As a mission application, attention is given to a spacecraft optical transceiver package (OPTRANSDAC) attached to a Mars rover vehicle. Also considered are a preliminary concept for a 1000-AU mission, and to a tentative long-range plan for NASA's deep space optical communications program.

  16. Space Engineering Technology (SET) Space Technology Institute

    NSDL National Science Digital Library

    Prince George's Community College (PGCC) and the NASA Goddard Space Flight Center (GSFC) in Greenbelt, MD. PGCC, GSFC, and NASA's corporate contractors (GCA) have jointly designed the Space Engineering Technology degree curriculum (electronic systems) and two additional degree options: Computer Systems Technology (programming) and Quality Assurance Technology (quality science). Each degree option has a minimum requirement of 64 credit hours. Target Audience: 2-4 Year College Students, 2-4 Year College Faculty/Administrators

  17. Affordable Space Tourism: SpaceStationSim

    NASA Technical Reports Server (NTRS)

    2006-01-01

    For over 5 years, people have been living and working in space on the International Space Station (ISS), a state-of-the-art laboratory complex orbiting high above the Earth. Offering a large, sustained microgravity environment that cannot be duplicated on Earth, the ISS furthers humankind s knowledge of science and how the body functions for extended periods of time in space all of which will prove vital on long-duration missions to Mars. On-orbit construction of the station began in November 1998, with the launch of the Russian Zarya Control Module, which provided battery power and fuel storage. This module was followed by additional components and supplies over the course of several months. In November 2000, the first ISS Expedition crew moved in. Since then, the ISS has continued to change and evolve. The space station is currently 240 feet wide, measured across the solar arrays, and 171 feet long, from the NASA Destiny Laboratory to the Russian Zvezda Habitation Module. It is 90 feet tall, and it weighs approximately 404,000 pounds. Crews inhabit a living space of about 15,000 cubic feet. To date, 90 scientific investigations have been conducted on the space station. New results from space station research, from basic science to exploration research, are being published each month, and more breakthroughs are likely to come. It is not all work on the space station, though. The orbiting home affords many of the comforts one finds on Earth. There is a weightless "weight room" and even a musical keyboard alongside research facilities. Holidays are observed, and with them, traditional foods such as turkey and cobbler are eaten, with lemonade to wash them down

  18. Storms in Space

    NASA Astrophysics Data System (ADS)

    Freeman, John W.

    2012-11-01

    Introduction; The cast of characters; Vignettes of the storm; 1. Two kinds of weather; 2. The saga of the storm; 3. Weather stations in space; 4. Lights in the night: the signature of the storm; 5. A walking tour of the magnetosphere; 6. The sun: where it all begins; 7. Nowcasting and forecasting storms in space; 8. Technology and the risks from storms in space; 9. A conversation with Joe Allen; 10. Manned exploration and space weather hazards; 11. The present and future of space weather forecasting; Mathematical appendix. A closer look; Glossary; Figure captions.

  19. System requirements. [Space systems

    SciTech Connect

    Austin, R.E.

    1982-06-01

    Requirements of future space systems, including large space systems, that operate beyond the space shuttle are discussed. Typical functions required of propulsion systems in this operational regime include payload placement, retrieval, observation, servicing, space debris control and support to large space systems. These functional requirements are discussed in conjunction with two classes of propulsion systems: (1) primary or orbit transfer vehicle (OTV) and (2) secondary or systems that generally operate within or relatively near an operational base orbit. Three propulsion system types are described in relation to these requirements: cryogenic OTV, teleoperator maneuvering system and a solar electric OTV.

  20. Space Acquired Photography

    USGS Publications Warehouse

    U.S. Geological Survey

    2008-01-01

    Interested in a photograph of the first space walk by an American astronaut, or the first photograph from space of a solar eclipse? Or maybe your interest is in a specific geologic, oceanic, or meteorological phenomenon? The U.S. Geological Survey (USGS) Earth Resources Observation and Science (EROS) Center is making photographs of the Earth taken from space available for search, download, and ordering. These photographs were taken by Gemini mission astronauts with handheld cameras or by the Large Format Camera that flew on space shuttle Challenger in October 1984. Space photographs are distributed by EROS only as high-resolution scanned or medium-resolution digital products.

  1. The Space Science Group

    NSDL National Science Digital Library

    1997-01-01

    The Space Science Group is part of the Division of Mathematics and Sciences at Northwestern State University in Natchitoches, La. The mission of The Space Science Group is to provide activities that encourage participation in math and science, build knowledge of basic concepts, teach basic science skill, and positively influence attitudes. The mission of The Space Science Group is to develop and implement programs which use aspects of the space program to motivate students to study mathematics and science. Many Space Science Group programs are described at the URL below.

  2. Space physics exhibits underway

    NASA Astrophysics Data System (ADS)

    DeVito, M. Catherine

    AGU is planning a new space science exhibit for the Smithsonian Institution's National Air and Space Museum in Washington that will help visitors come to an understanding of space science as a comprehensive, interdisciplinary, and exciting field. The title of the exhibit is “Electric Space: Our Earth-Sun Environment.” The exhibit's five modules will include demonstrations of the effects of particle and field radiation on humans and satellites in space and on human technology on the ground. The project also includes a larger traveling version that will visit science and technology centers throughout the United States. The first exhibit is planned to open at the Air and Space Museum in late summer or early fall 1992, in time for International Space Year activities; the traveling exhibit will begin touring in early 1993.

  3. Ion chemistry in space.

    PubMed

    Larsson, M; Geppert, W D; Nyman, G

    2012-06-01

    We review the gas-phase chemistry in extraterrestrial space that is driven by reactions with atomic and molecular ions. Ions are ubiquitous in space and are potentially responsible for the formation of increasingly complex interstellar molecules. Until recently, positively charged atoms and molecules were the only ions known in space; however, this situation has changed with the discovery of various molecular anions. This review covers not only the observation, distribution and reactions of ions in space, but also laboratory-based experimental and theoretical methods for studying these ions. Recent results from space-based instruments, such as those on the Cassini-Huygens space mission and the Herschel Space Observatory, are highlighted. PMID:22790651

  4. Space Suit Thermal Dynamics

    NASA Technical Reports Server (NTRS)

    Campbell, Anthony B.; Nair, Satish S.; Miles, John B.; Iovine, John V.; Lin, Chin H.

    1998-01-01

    The present NASA space suit (the Shuttle EMU) is a self-contained environmental control system, providing life support, environmental protection, earth-like mobility, and communications. This study considers the thermal dynamics of the space suit as they relate to astronaut thermal comfort control. A detailed dynamic lumped capacitance thermal model of the present space suit is used to analyze the thermal dynamics of the suit with observations verified using experimental and flight data. Prior to using the model to define performance characteristics and limitations for the space suit, the model is first evaluated and improved. This evaluation includes determining the effect of various model parameters on model performance and quantifying various temperature prediction errors in terms of heat transfer and heat storage. The observations from this study are being utilized in two future design efforts, automatic thermal comfort control design for the present space suit and design of future space suit systems for Space Station, Lunar, and Martian missions.

  5. Space Food Systems Laboratory

    NASA Technical Reports Server (NTRS)

    Perchonok, Michele; Russo, Dane M. (Technical Monitor)

    2001-01-01

    The Space Food Systems Laboratory (SFSL) is a multipurpose laboratory responsible for space food and package research and development. It is located on-site at Johnson Space Center in Building 17. The facility supports the development of flight food, menus, packaging and food related hardware for Shuttle, International Space Station, and Advanced Life Support food systems. All foods used to support NASA ground tests and/or missions must meet the highest standards before they are 'accepted' for use on actual space flights. The foods are evaluated for nutritional content, sensory acceptability, safety, storage and shelf life, and suitability for use in micro-gravity. The food packaging is also tested to determine its functionality and suitability for use in space. Food Scientist, Registered Dieticians, Packaging Engineers, Food Systems Engineers, and Technicians staff the Space Food Systems Laboratory.

  6. On the Critical Ionization Velocity Effect in Interstellar Space and Possible Detection of Related Continuum Emission

    E-print Network

    Verschuur, Gerrit L

    2007-01-01

    Interstellar neutral hydrogen (HI) emission spectra manifest several families of linewidths whose numerical values (34, 13 & 6 km/s) appear to be related to the critical ionization velocities (CIVs) of the most abundant interstellar atomic species. Extended new analysis of HI emission profiles shows that the 34 km/s wide component, probably corresponding to the CIV for helium, is pervasive. The 34 km/s wide linewidth family is found in low-velocity (local) neutral hydrogen (HI) profiles as well as in the so-called high-velocity clouds. In addition, published studies of HI linewidths found in the Magellanic Stream, Very-High-Velocity Clouds, and Compact High-Velocity Clouds, all of which are believed to be intergalactic, have noted that typical values are of the same order. If the critical ionization velocity effect does play a role in interstellar space it may be expected to produce locally enhanced electron densities where rapidly moving neutral gas masses interact with surrounding plasma. Evidence is pr...

  7. First results from the HST Grism Lens-Amplified Survey from Space (GLASS)

    NASA Astrophysics Data System (ADS)

    WANG, XIN; Schmidt, K. B.; Treu, T.; GLASS Team

    2014-01-01

    GLASS is a cycle-21 large program with the Hubble Space Telescope, targeting 10 massive clusters, including the 6 Frontier Fields, using the WFC3 and ACS grisms. The program consists of 140 primary orbits and 140 parallel orbits. Using the clusters as cosmic telescopes, GLASS is taking spectra of faint background galaxies with unprecedented sensitivity and angular resolution. GLASS has 3 primary science drivers, although a variety of other science investigations are possible in combination with existing and planned imaging campaigns. The first key science goal is to shed light upon the role of galaxies in reionizing the universe, the topology of high redshift intergalactic/interstellar medium and Lyman alpha escape fraction. The second key science goal is to study gas accretion, star formation and outflows by mapping spatially resolved star formation and metallicity gradients in galaxies at z=1.3-2.3. The third key science goal is to study the environmental dependence of galaxy evolution, by mapping spatially resolved star formation in galaxies in the cluster cores and infalling regions. We present the details of the program and results from the first cluster observed by GLASS MACS0717.5+3745.

  8. Making space law relevant to basic space science in the commercial space age

    Microsoft Academic Search

    Sriram Swaminathan

    2005-01-01

    Space science has been at the heart of humanity's activity in space, a fact reflected in the body of space law set up to regulate such activity. The increase in commercial utilisation of space may threaten the conduct of space science; reform of space law, however, could alleviate this situation. Using the examples of radio and light interference, and space

  9. 46 CFR 108.205 - Wash spaces; toilet spaces; and shower spaces.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ...false Wash spaces; toilet spaces; and shower spaces. 108.205 Section 108.205...205 Wash spaces; toilet spaces; and shower spaces. (a) For the purposes of this...facility” means a toilet, washing, or shower space that is accessible only from...

  10. 46 CFR 108.205 - Wash spaces; toilet spaces; and shower spaces.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ...false Wash spaces; toilet spaces; and shower spaces. 108.205 Section 108.205...205 Wash spaces; toilet spaces; and shower spaces. (a) For the purposes of this...facility” means a toilet, washing, or shower space that is accessible only from...

  11. 46 CFR 108.205 - Wash spaces; toilet spaces; and shower spaces.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ...false Wash spaces; toilet spaces; and shower spaces. 108.205 Section 108.205...205 Wash spaces; toilet spaces; and shower spaces. (a) For the purposes of this...facility” means a toilet, washing, or shower space that is accessible only from...

  12. Compact spaces and their applications in Banach space theory

    E-print Network

    Tebbens, Jurjen Duintjer

    Compact spaces and their applications in Banach space theory Ond°ej Kalenda Charles University of Banach spaces . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9 2.2. Summary.3. Decompositions of nonseparable Banach spaces . . . . . . . . . . . . . . . 23 2.4. Summary of Chapter 3

  13. National Aeronautics and Space Administration Human Space Exploration

    E-print Network

    Waliser, Duane E.

    National Aeronautics and Space Administration Human Space Exploration Framework Summary For Public Release 1 #12;Overview Context and approach for human space exploration Key guiding time. Human Space Exploration Architecture Planning Human spaceflight (HSF) programs

  14. National Aeronautics and Space Administration Commercial Space Committee

    E-print Network

    Waliser, Duane E.

    __________________________________ ________________________________________ National Aeronautics and Space Administration Commercial Space Committee of the NASA Advisory Council November 26, 2012 NASA Commercial Space Committee Commercial Space Committee Meeting report prepared by Elizabeth Sheley #12;NAC

  15. National Aeronautics and Space Administration Commercial Space Committee

    E-print Network

    Waliser, Duane E.

    ___________________________________ __________________________________ National Aeronautics and Space Administration Commercial Space Committee of the NASA Advisory Council July 30, 2013 NASA Commercial Space Committee Commercial Space Committee Meeting report prepared by Jill Hacker Zantech IT #12

  16. National Aeronautics and Space Administration Space Life and Physical Sciences

    E-print Network

    Waliser, Duane E.

    National Aeronautics and Space Administration Space Life and Physical Sciences D National Laboratory management organization (CASIS) #12;National Aeronautics and Space Administration #12;National Aeronautics and Space Administration geneLAB Campaign Progress To move forward

  17. International space station

    NASA Astrophysics Data System (ADS)

    DeLucas, Lawrence J.

    1996-02-01

    The International Space Station represents the largest scientific and technological cooperative program in history, drawing on the resources of thirteen nations. The early stages of construction will involve significant participation from the Russian Space Agency (RSA), numerous nations of the European Space Agency (ESA), and the space agencies of Canada (CSA), Japan (NASDA) and the United States Space Agency (NASA). Its purpose is to place a unique, highly capable laboratory in tower orbit, where high value scientific research can be performed in microgravity. In addition to providing facilities where an international crew of six astronaut-scientists can live and work in space, it will provide important laboratory research facilities for performing basic research in life science, biomedical and material sciences, as well as space and engineering technology development which cannot be accomplished on Earth. The Space Station will be comprised of numerous interlocking components which are currently being constructed on Earth. Space Station will be assembled in orbit over a period of time and will provide several experimentation modules as well as habitation modules and interfaces for logistic modules. Including the four extensive solar rays from which it will draw electrical power, the Station will measure more than 300 feet wide by 200 feet long. This paper will present an overview of the various phases of construction of the Space Station and the planned science thought will be performed during the construction phase and after completion.

  18. Public choice economics and space policy: realising space tourism

    Microsoft Academic Search

    Patrick Collins

    2001-01-01

    Government space agencies have the statutory responsibility to suport the commercialisation of space activities. NASA's 1998 report “General Public Space Travel and Tourism” concluded that passenger space travel can start using already existing technology, and is likely to grow into the largest commercial activity in space: it is therefore greatly in taxpayers' economic interest that passenger space travel and accommodation

  19. Space Resources Roundtable 2

    NASA Technical Reports Server (NTRS)

    Ignatiev, A.

    2000-01-01

    Contents include following: Developing Technologies for Space Resource Utilization - Concept for a Planetary Engineering Research Institute. Results of a Conceptual Systems Analysis of Systems for 200 m Deep Sampling of the Martian Subsurface. The Role of Near-Earth Asteroids in Long-Term Platinum Supply. Core Drilling for Extra-Terrestrial Mining. Recommendations by the "LSP and Manufacturing" Group to the NSF-NASA Workshop on Autonomous Construction and Manufacturing for Space Electrical Power Systems. Plasma Processing of Lunar and Planetary Materials. Percussive Force Magnitude in Permafrost. Summary of the Issues Regarding the Martian Subsurface Explorer. A Costing Strategy for Manufacturing in Orbit Using Extraterrestrial Resources. Mine Planning for Asteroid Orebodies. Organic-based Dissolution of Silicates: A New Approach to Element Extraction from LunarRegohth. Historic Frontier Processes Active in Future Space-based Mineral Extraction. The Near-Earth Space Surveillance (NIESS) Mission: Discovery, Tracking, and Characterization of Asteroids, Comets, and Artificial Satellites with a microsatellite. Privatized Space Resource Property Ownership. The Fabrication of Silicon Solar Cells on the Moon Using In-Situ Resources. A New Strategy for Exploration Technology Development: The Human Exploration and Development of Space (HEDS) Exploratiori/Commercialization Technology Initiative. Space Resources for Space Tourism. Recovery of Volatiles from the Moon and Associated Issues. Preliminary Analysis of a Small Robot for Martian Regolith Excavation. The Registration of Space-based Property. Continuous Processing with Mars Gases. Drilling and Logging in Space; An Oil-Well Perspective. LORPEX for Power Surges: Drilling, Rock Crushing. An End-To-End Near-Earth Asteroid Resource Exploitation Plan. An Engineering and Cost Model for Human Space Settlement Architectures: Focus on Space Hotels and Moon/Mars Exploration. The Development and Realization of a Silicon-60-based Economy in CisLunar Space. Our Lunar Destiny: Creating a Lunar Economy. Cost-Effective Approaches to Lunar Passenger Transportation. Lunar Mineral Resources: Extraction and Application. Space Resources Development - The Link Between Human Exploration and the Long-term Commercialization of Space. Toward a More Comprehensive Evaluation of Space Information. Development of Metal Casting Molds by Sol-Gel Technology Using Planetary Resources. A New Concept in Planetary Exploration: ISRU with Power Bursts. Bold Space Ventures Require Fervent Public Support. Hot-pressed Iron from Lunar Soil. The Lunar Dust Problem: A Possible Remedy. Considerations on Use of Lunar Regolith in Lunar Constructions. Experimental Study on Water Production by Hydrogen Reduction of Lunar Soil Simulant in a Fixed Bed Reactor.

  20. National Aeronautics and Space Administration

    E-print Network

    Lüttgen, Gerald

    National Aeronautics and Space Administration Langley Research Center Hampton, Virginia 23681 state space generators 30 . This work was supported by the National Aeronautics and Space Administration State-space Generation Gianfranco Ciardo The College of William & Mary, Williamsburg, Virginia Gerald

  1. Gymnastics in Phase Space

    SciTech Connect

    Chao, Alexander Wu; /SLAC

    2012-03-01

    As accelerator technology advances, the requirements on accelerator beam quality become increasingly demanding. Facing these new demands, the topic of phase space gymnastics is becoming a new focus of accelerator physics R&D. In a phase space gymnastics, the beam's phase space distribution is manipulated and precision tailored to meet the required beam qualities. On the other hand, all realization of such gymnastics will have to obey accelerator physics principles as well as technological limitations. Recent examples of phase space gymnastics include Emittance exchanges, Phase space exchanges, Emittance partitioning, Seeded FELs and Microbunched beams. The emittance related topics of this list are reviewed in this report. The accelerator physics basis, the optics design principles that provide these phase space manipulations, and the possible applications of these gymnastics, are discussed. This fascinating new field promises to be a powerful tool of the future.

  2. Space biology research development

    NASA Technical Reports Server (NTRS)

    Bonting, Sjoerd L.

    1993-01-01

    The purpose of the Search for Extraterrestrial Intelligence (SETI) Institute is to conduct and promote research related activities regarding the search for extraterrestrial life, particularly intelligent life. Such research encompasses the broad discipline of 'Life in the Universe', including all scientific and technological aspects of astronomy and the planetary sciences, chemical evolution, the origin of life, biological evolution, and cultural evolution. The primary purpose was to provide funding for the Principal Investigator to collaborate with the personnel of the SETI Institute and the NASA-Ames Research center in order to plan and develop space biology research on and in connection with Space Station Freedom; to promote cooperation with the international partners in the space station; to conduct a study on the use of biosensors in space biology research and life support system operation; and to promote space biology research through the initiation of an annual publication 'Advances in Space Biology and Medicine'.

  3. Space resources. Overview

    NASA Astrophysics Data System (ADS)

    McKay, Mary Fae; McKay, David S.; Duke, Michael B.

    Space resources must be used to support life on the Moon and in the exploration of Mars. Just as the pioneers applied the tools they brought with them to resources they found along the way rather than trying to haul all their needs over a long supply line, so too must space travelers apply their high technology tools to local resources. This overview describes the findings of a study on the use of space resources in the development of future space activities and defines the necessary research and development that must precede the practical utilization of these resources. Space resources considered included lunar soil, oxygen derived from lunar soil, material retrieved from near-Earth asteroids, abundant sunlight, low gravity, and high vacuum. The study participants analyzed the direct use of these resources, the potential demand for products from them, the techniques for retrieving and processing space resources, the necessary infrastructure, and the economic tradeoffs.

  4. Representing auditory space

    Microsoft Academic Search

    Sandra R. Palef; Rand B. Nickerson

    1978-01-01

    Ontario Institute for Studtes tn Education, University of Toronto, Toronto, Canada M5S 1 V6 Auditory space has been characterized\\u000a as an entity without bound or dimension, as opposed to visual space which is limited in three dimensions. While there is evidence\\u000a that visual space may be represented mentally in terms of contrastive values on these dimensions, no evidence exists concerning

  5. Space Weather Media Viewer

    NSDL National Science Digital Library

    2011-01-01

    This is version 3 of the space Weather Media Viewer, created to work with the space Weather Action Center to see near-real time data and to provide additional images and resources available for educational use. It features easy downloads that can also be added to news reports and space weather reports. It was designed for ease in adding any media (videos, images) data.

  6. Intelligent spaces: An overview

    Microsoft Academic Search

    Bin Liu; Fei-Yue Wang; Jason Geng; Qingming Yao; Hui Gao; Buqing Zhang

    2007-01-01

    This paper presents a brief review of state-of-the- art research in the field of intelligent spaces. With the increased availability of smart sensors and context-aware appliances that are equipped with embedded computing and communication capability, the intelligent space concept have found widespread applications. First, we introduce the concept, and applications of intelligent spaces. Then we explore research issues on the

  7. THz Sources for Space

    NASA Technical Reports Server (NTRS)

    Siegel, Peter H.; Ward, John; Maiwald, Frank; Mehdi, Imran

    2007-01-01

    Terahertz is the primary frequency for line and continuum radiation from cool (5-100K) gas (atoms and molecules) and dust. This viewgraph presentation reviews the reasons for the interest in Terahertz Space Applications; the Terahertz Space Missions: in the past, present and planned for the future, Terahertz source requirements and examples of some JPL instruments; and a case study for a flight deliverable: THz Local Oscillators for ESA s Herschel Space Telescope

  8. Space Odyssey Gift Shop

    NASA Technical Reports Server (NTRS)

    2000-01-01

    The Space Odyssey Gift Shop located in StenniSphere at the John C. Stennis Space Center in Hancock County, Miss., offers every visitor the opportunity to go home with 'the right stuff' from his or her StenniSphere visit. The gift shop is located just inside the front doors to StenniSphere and offers a wide range of space-related apparel, memorabilia, toys, books, mission patches and more.

  9. Rocket and Space Technology

    NSDL National Science Digital Library

    Braeuning, Robert

    This site, created by author Robert Braeuning, features material on orbital mechanics, propulsion, rocket hardware, space centers and missions. It includes definitions of important terms and black-and-white diagrams. The page also features information on rocket propellants, rocket propulsion, orbital mechanics, spacecraft systems, vehicle specifications, launch vehicles, manned space flights, planetary spacecraft, and lunar spacecraft. A glossary and discussion forum are also provided. This is a nice resource for a overview of all things involving rockets or other space technologies.

  10. Space station communications

    Microsoft Academic Search

    C. L. Cuccia

    1983-01-01

    A concise history of the various types of communications that have been used in low-earth-orbit vehicles and form the basis of the various types of communications and communication requirements that can be realized in space-station developments over the next decade is presented. The Space Shuttle can be assumed to be a prototype space station in the tradition of Apollo and

  11. Basics of Space Flight

    NSDL National Science Digital Library

    This training module was designed to help the user identify and grasp basic concepts associated with space travel and deep space missions. Separate sections deal with topics such as the physical environment of space (solar system, gravity, orbital mechanics), flight projects (mission concepts, system requirements, design, onboard systems and instruments), and flight operations (launch, cruise, encounter). Links to related topics are embedded in the text.

  12. A Week for Space

    NSDL National Science Digital Library

    Diane Comstock

    2008-09-01

    Space Week focuses on concepts that enable students to make concrete observations in the early grades (K--2) and move to concepts that help students develop their internet research and writing skills in middle and upper grades (Grades 3--5), and culminates with the development of science investigation design skills (Grade 6). To help launch your students' interest in space science, this article presents inquiry-based space lessons, which are aligned with the National Science Education Standards.

  13. Aging and space travel

    NASA Technical Reports Server (NTRS)

    Mohler, S. R.

    1982-01-01

    The matter of aging and its relation to space vehicle crewmembers undertaking prolonged space missions is addressed. The capabilities of the older space traveler to recover from bone demineralization and muscle atrophy are discussed. Certain advantages of the older person are noted, for example, a greater tolerance of monotony and repetitious activities. Additional parameters are delineated including the cardiovascular system, the reproductive system, ionizing radiation, performance, and group dynamics.

  14. Space Station - early

    NASA Technical Reports Server (NTRS)

    1961-01-01

    Manned Space Laboratory Research. James Hansen wrote: 'Testing indicated that the inflatable torus could be packaged around the hub so that it occupied only 2 percent of its inflated volume.' 'The first idea for an inflatable station was the Erectable Torus Manned Space Laboratory. A Langley space station team led by Paul Hill and Emanuel 'Manny' Schnitzer developed the concept with the help of the Goodyear Aircraft Corporation.'

  15. Space Group Symmetry

    NSDL National Science Digital Library

    In this problem set, students are given space group symmetry diagrams for primitive (P) orthorhombic space groups. For each diagram they must write down the symmetry axis (either 2 or 21) that is parallel to each major axis, and give the symmetry plane (a, b, c, n, or m) that is normal (perpendicular)to each. They must also give the simplified Hermann-Mauguin symbol for the space group.

  16. Space technology research plans

    NASA Technical Reports Server (NTRS)

    Hook, W. Ray

    1992-01-01

    Development of new technologies is the primary purpose of the Office of Aeronautics and Space Technology (OAST). OAST's mission includes the following two goals: (1) to conduct research to provide fundamental understanding, develop advanced technology and promote technology transfer to assure U.S. preeminence in aeronautics and to enhance and/or enable future civil space missions: and (2) to provide unique facilities and technical expertise to support national aerospace needs. OAST includes both NASA Headquarters operations as well as programmatic and institutional management of the Ames Research Center, the Langley Research Center and the Lewis Research Center. In addition. a considerable portion of OAST's Space R&T Program is conducted through the flight and science program field centers of NASA. Within OAST, the Space Technology Directorate is responsible for the planning and implementation of the NASA Space Research and Technology Program. The Space Technology Directorate's mission is 'to assure that OAST shall provide technology for future civil space missions and provide a base of research and technology capabilities to serve all national space goals.' Accomplishing this mission entails the following objectives: y Identify, develop, validate and transfer technology to: (1) increase mission safety and reliability; (2) reduce flight program development and operations costs; (3) enhance mission performance; and (4) enable new missions. Provide the capability to: (1) advance technology in critical disciplines; and (2) respond to unanticipated mission needs. In-space experiments are an integral part of OAST's program and provides for experimental studies, development and support for in-space flight research and validation of advanced space technologies. Conducting technology experiments in space is a valuable and cost effective way to introduce advanced technologies into flight programs. These flight experiments support both the R&T base and the focussed programs within OAST.

  17. History of Space Exploration

    NSDL National Science Digital Library

    Users can choose from an extensive selection of links to resources for use in the study of the history of space exploration. The links provide access to historic information and publications, chronologies, and mission summaries for American, Russian, European, and other space missions. For educators, there are links to guides to robotic spacecraft and to observing the space shuttle in orbit. Links are also provided to a variety of spacecraft homepages and to other topics such as a primer on the basics of space flight, the Apollo lunar surface journals, and the NASA historic archives.

  18. The space station

    NASA Technical Reports Server (NTRS)

    Munoz, Abraham

    1988-01-01

    Conceived since the beginning of time, living in space is no longer a dream but rather a very near reality. The concept of a Space Station is not a new one, but a redefined one. Many investigations on the kinds of experiments and work assignments the Space Station will need to accommodate have been completed, but NASA specialists are constantly talking with potential users of the Station to learn more about the work they, the users, want to do in space. Present configurations are examined along with possible new ones.

  19. SpaceRef

    NSDL National Science Digital Library

    This resource is aimed at professionals and informed users with a strong interest in astronomy and astronautics, and the second can be enjoyed by kids of all ages. While the content in some of the multiple categories in SpaceRef's Space Directory is currently a little thin, the site is clearly designed from the ground-up to host a wide array of space resources. In addition to the directory, the site also features breaking news, analysis, full-text briefs from NASA and the European Space Agency (ESA), a calendar of events and launches, and special sections on current missions.

  20. Loaded sectioned space elevator

    NASA Astrophysics Data System (ADS)

    Sadov, Yu. A.; Nuralieva, A. B.

    2015-05-01

    New super strong materials discovered at the end of the 20th century have caused a surge of activity in work devoted to the space elevator (SE). A rather complete concept of the SE has been formulated. This concept, having many advantages, possesses, nevertheless, limited capabilities and insufficient reliability. In this paper we present a modified space elevator concept [1] that has higher reliability and extended capabilities. Such a construction is more complicated and its design is more expensive, so it can be realized only as a part of a large-scale space program. Inclusion of a space elevator in such a program will facilitate development of new technologies.

  1. The deep space network

    NASA Technical Reports Server (NTRS)

    1977-01-01

    Presented is Deep Space Network (DSN) progress in flight project support, tracking and data acquisition (TDA) research and technology, network engineering, hardware and software implementation, and operations.

  2. The deep space network

    NASA Technical Reports Server (NTRS)

    1975-01-01

    Summaries are given of Deep Space Network progress in flight project support, tracking and data acquisition research and technology, network engineering, hardware and software implementation, and operations.

  3. Space Transportation Propulsion Systems

    NASA Technical Reports Server (NTRS)

    Liou, Meng-Sing; Stewart, Mark E.; Suresh, Ambady; Owen, A. Karl

    2001-01-01

    This report outlines the Space Transportation Propulsion Systems for the NPSS (Numerical Propulsion System Simulation) program. Topics include: 1) a review of Engine/Inlet Coupling Work; 2) Background/Organization of Space Transportation Initiative; 3) Synergy between High Performance Computing and Communications Program (HPCCP) and Advanced Space Transportation Program (ASTP); 4) Status of Space Transportation Effort, including planned deliverables for FY01-FY06, FY00 accomplishments (HPCCP Funded) and FY01 Major Milestones (HPCCP and ASTP); and 5) a review current technical efforts, including a review of the Rocket-Based Combined-Cycle (RBCC), Scope of Work, RBCC Concept Aerodynamic Analysis and RBCC Concept Multidisciplinary Analysis.

  4. Multimegawatt space power reactors

    SciTech Connect

    Dearien, J.A.; Whitbeck, J.F.

    1989-01-01

    In response to the need of the Strategic Defense Initiative (SDI) and long range space exploration and extra-terrestrial basing by the National Air and Space Administration (NASA), concepts for nuclear power systems in the multi-megawatt levels are being designed and evaluated. The requirements for these power systems are being driven primarily by the need to minimize weight and maximize safety and reliability. This paper will discuss the present requirements for space based advanced power systems, technological issues associated with the development of these advanced nuclear power systems, and some of the concepts proposed for generating large amounts of power in space. 31 figs.

  5. Space Station - early

    NASA Technical Reports Server (NTRS)

    1961-01-01

    Manned Space Laboratory Research. James Hansen wrote: 'Langley built and tested various models of the Erectable Torus Manned Space Laboratory, including a full-scale research model constructed by Goodyear.' The uninflated station was packed around a 24-foot diameter torus and could be launched inside a rocket. 'The first idea for an inflatable station was the Erectable Torus Manned Space Laboratory. A Langley space station team led by Paul Hill and Emanuel 'Manny' Schnitzer developed the concept with the help of the Goodyear Aircraft Corporation.'

  6. Kennedy Space Center

    NASA Technical Reports Server (NTRS)

    Griffin, Amanda

    2012-01-01

    Among 2011's many accomplishments, we safely retired the Space Shuttle Program after 30 incredible years; completed the International Space Station and are taking steps to enable it to reach its full potential as a multi-purpose laboratory; and helped to expand scientific knowledge with missions like Aquarius, GRAIL, and the Mars Science Laboratory. Responding to national budget challenges, we are prioritizing critical capabilities and divesting ourselves of assets no longer needed for NASA's future exploration programs. Since these facilities do not have to be maintained or demolished, the government saves money. At the same time, our commercial partners save money because they do not have to build new facilities. It is a win-win for everyone. Moving forward, 2012 will be even more historically significant as we celebrate the 50th Anniversary of Kennedy Space Center. In the coming year, KSC will facilitate commercial transportation to low-Earth orbit and support the evolution of the Space Launch System and Orion crew vehicle as they ready for exploration missions, which will shape how human beings view the universe. While NASA's Vision is to lead scientific and technological advances in aeronautics and space for a Nation on the frontier of discovery KSC's vision is to be the world's preeminent launch complex for government and commercial space access, enabling the world to explore and work in space. KSC's Mission is to safely manage, develop, integrate, and sustain space systems through partnerships that enable innovative, diverse access to space and inspires the Nation's future explorers.

  7. Adventures in Space Medicine

    NASA Technical Reports Server (NTRS)

    Billica, Roger D.

    1999-01-01

    Human space flight experience has demonstrated a variety of hazards and risks to health and performance. In developing ways to help respond to these issues, the field of space medicine has developed a comprehensive program of space flight health risk management that has resulted in positive contributions to medicine and society in general. Examples include accelerated focus on critical health issues such as aging and osteoporosis, and development of new technologies such as non-invasive diagnostic testing for diabetics. The role of health care professionals in human space exploration represents a fulfillment of new adventures and expanding frontiers.

  8. On Multi-Vector Spaces

    E-print Network

    Linfan Mao

    2005-10-22

    A Smarandache multi-space is a union of $n$ spaces $A_1,A_2,..., A_n$ with some additional conditions holding. Combining Smarandache multi-spaces with linear vector spaces in classical linear algebra, the conception of multi-vector spaces is introduced. Some characteristics of a multi-vector space are obtained in this paper.

  9. Extragalactic Radio Jets and Intergalactic Medium 2

    NASA Technical Reports Server (NTRS)

    Birkinshaw, Mark

    2000-01-01

    During the mid 1990s, the ROSAT satellite provided the highest resolution X-ray imaging, with useful X-ray spectroscopy, and excellent sensitivity. ROSAT"s PSPC and HRI instruments gave us our first high-quality data on the AGN phenomenon in nearby galaxies - the central theme of this research project. Initially this project concentrated on separating the AGN-related component of the X-ray emission from thermal radiation from the surrounding atmospheres in radio galaxies. There was ample reason to believe that this separation would be possible, although earlier work had taken the view that the X-ray emission from radio galaxies is either wholly AGN-related (and hence of sub-arcsec scale), or wholly from the galaxy and cluster atmospheres (and hence of scales - 10 arcsec or more in the low-redshift radio galaxies that we chose to study). First with the PSPC, and then with the HRI, we proved that a wide range of AGN core X ray emissivities could be found, and that the generic radio galaxy produces both AGN-related and atmosphere-related X-radiation. We demonstrated that there is a close relationship between the core X-ray power and the core radio power, and found instances in which the hot atmospheres of the galaxies must be participating in cooling flows, and other cases where those atmospheres are relatively stable. In some cases, there is a clear active relationship between the extended radio emission and the X-ray atmospheres: thus in NGC 326, we interpret the distorted radio structure as evidence of buoyancy as the radio plasma rises through the cluster atmosphere. In 3C 449, we can see that the radio plasma is displacing the X-ray emitting gas. In a further case (NGC 1265), we hoped that the motion of a radio galaxy through a cluster atmosphere would be apparent though the wake that it might establish - unfortunately, other structure in the atmosphere of the Perseus cluster tends to dominate our X-ray image, and no useful limits could be placed on the strength of the wake. In the light of so-called "unified" models of AGN, it is expected that the low-power radio galaxies studied under these programmes are the unbeamed counterparts of BL Lac objects. Accordingly, we predicted that BL Lac objects, as a class, should show X-ray halos from atmospheres similar to those associated with radio galaxies. The difficulty with studying this is that BL Lac objects tend to be X-ray bright, and the halos then vanish under the wings of the point response function. We found a BL Lac with less of a dynamic range problem, mapped it with the ROSAT HRI, and duly found an atmosphere (Hardcastle et al. 1999). Unfortunately for unification models, this atmosphere is exceptionally dense, so that it must be participating in an intense cooling flow. The implications of this for unification models are far from clear, and further work is under way.

  10. Intergalactic Baryons in the Local Universe

    E-print Network

    Charles W. Danforth

    2008-12-02

    Simulations predict that shocks from large-scale structure formation and galactic winds have reduced the fraction of baryons in the warm, photoionized phase (the Lya forest) from nearly 100% in the early universe to less than 50% today. Some of the remaining baryons are predicted to lie in the warm-hot ionized medium (WHIM) phase at T=10^5-10^7 K, but the quantity remains a highly tunable parameter of the models. Modern UV spectrographs have provided unprecedented access to both the Lya forest and potential WHIM tracers at z~0, and several independent groups have constructed large catalogs of far-UV IGM absorbers along ~30 AGN sight lines. There is general agreement between the surveys that the warm, photoionized phase makes up ~30% of the baryon budget at z~0. Another ~10% can be accounted for in collapsed structures (stars, galaxies, etc.). However, interpretation of the ~100 high-ion (OVI, etc) absorbers at z<0.5 is more controversial. These species are readily created in the shocks expected to exist in the IGM, but they can also be created by photoionization and thus not represent WHIM material. Given several pieces of observational evidence and theoretical expectations, I argue that most of the observed OVI absorbers represent shocked gas at T~300,000 K rather than photoionized gas at T<30,000 K, and they are consequently valid tracers of the WHIM phase. Under this assumption, enriched gas at T=10^5-10^6 K can account for ~10% of the baryon budget at z<0.5, but this value may increase when bias and incompleteness are taken into account and help close the gap on the 50% of the baryons still "missing".

  11. Quasars as probes of the intergalactic medium

    NASA Technical Reports Server (NTRS)

    Green, R. F.; Bechtold, J.

    1984-01-01

    Spectral energy distributions for 10 high red shift quasars in the wavelength range 1250 to 10,000 A were obtained by IUE. A pronounced steepening is detected shortward of 1200 A, which correlates well with quasar red shift, but poorly with luminosity. The observed slope change is explained by Lyman continuum absorption from the strongest 5% of the Lyman alpha forest lines, identified with the low column density metal containing systems. Reddening may also contribute to the steepening, but a much lower neutral gas to dust ratio than that found in the Galaxy is required. Optically thick Lyman limit discontinuities are seen with zabs zem. These systems are metal containing, constant in comoving density with epoch, and require in L* galaxy to have a cross section of 5 to 10 Holmberg radii.

  12. Space Radiation Protection, Space Weather, and Exploration

    NASA Technical Reports Server (NTRS)

    Zapp, Neal; Fry, Dan; Lee, Kerry

    2010-01-01

    Management of crew exposure to radiation is a major concern for manned spaceflight and will be even more important for the modern concept of longer-duration exploration. The inherent protection afforded to astronauts by the magnetic field of the Earth in Low Earth Orbit (LEO) makes operations on the space shuttle or space station very different from operations during a deep space exploration mission. In order to experience significant radiation-derived Loss of Mission (LOM) or Loss of Crew (LOC) risk for LEO operations, one is almost driven to dictate extreme duration or to dictate an extreme sequence of solar activity. Outside of the geo-magnetosphere, however, this scenario changes dramatically. Exposures to the same event on the ISS and on the surface of the Moon may differ by multiple orders of magnitude. This change in magnitude, coupled with the logistical constraints present in implementing any practical operational mitigation make situational awareness with regard to space weather a limiting factor for our ability to conduct exploration operations. With these differences in risk to crew, vehicle and mission in mind, we present the status of the efforts currently underway as the required development to enable exploration operations. The changes in the operating environment as crewed operations begin to stretch away from the Earth are changing the way we think about the lines between research and operations . The real, practical work to enable a permanent human presence away from Earth has already begun

  13. Today's Space Weather Space Weather Case Studies

    E-print Network

    ], and grounding is difficult Hydro-Quebec's power grid is, within 90-sec of storm onset ! · These estimations vary on region as well as the initial power plant the power comes from. Loss: Who Pays? #12 tank on Space ShuQle trips alarms Impacts #12;Quebec electrical blackout: "GIC

  14. Physiologic adaptation to space - Space adaptation syndrome

    NASA Technical Reports Server (NTRS)

    Vanderploeg, J. M.

    1985-01-01

    The adaptive changes of the neurovestibular system to microgravity, which result in space motion sickness (SMS), are studied. A list of symptoms, which range from vomiting to drowsiness, is provided. The two patterns of symptom development, rapid and gradual, and the duration of the symptoms are described. The concept of sensory conflict and rearrangements to explain SMS is being investigated.

  15. International Space Station from Space Shuttle Endeavour

    NASA Technical Reports Server (NTRS)

    2007-01-01

    The crew of the Space Shuttle Endeavour took this spectacular image of the International Space Station during the STS118 mission, August 8-21, 2007. The image was acquired by an astronaut through one of the crew cabin windows, looking back over the length of the Shuttle. This oblique (looking at an angle from vertical, rather than straight down towards the Earth) image was acquired almost one hour after late inspection activities had begun. The sensor head of the Orbiter Boom Sensor System is visible at image top left. The entire Space Station is visible at image bottom center, set against the backdrop of the Ionian Sea approximately 330 kilometers below it. Other visible features of the southeastern Mediterranean region include the toe and heel of Italy's 'boot' at image lower left, and the western coastlines of Albania and Greece, which extend across image center. Farther towards the horizon, the Aegean and Black Seas are also visible. Featured astronaut photograph STS118-E-9469 was acquired by the STS-118 crew on August 19, 2007, with a Kodak 760C digital camera using a 28 mm lens, and is provided by the ISS Crew Earth Observations experiment and Image Science and Analysis Laboratory at Johnson Space Center.

  16. Cognitive Neuroscience in Space

    PubMed Central

    De la Torre, Gabriel G.

    2014-01-01

    Humans are the most adaptable species on this planet, able to live in vastly different environments on Earth. Space represents the ultimate frontier and a true challenge to human adaptive capabilities. As a group, astronauts and cosmonauts are selected for their ability to work in the highly perilous environment of space, giving their best. Terrestrial research has shown that human cognitive and perceptual motor performances deteriorate under stress. We would expect to observe these effects in space, which currently represents an exceptionally stressful environment for humans. Understanding the neurocognitive and neuropsychological parameters influencing space flight is of high relevance to neuroscientists, as well as psychologists. Many of the environmental characteristics specific to space missions, some of which are also present in space flight simulations, may affect neurocognitive performance. Previous work in space has shown that various psychomotor functions degrade during space flight, including central postural functions, the speed and accuracy of aimed movements, internal timekeeping, attentional processes, sensing of limb position and the central management of concurrent tasks. Other factors that might affect neurocognitive performance in space are illness, injury, toxic exposure, decompression accidents, medication side effects and excessive exposure to radiation. Different tools have been developed to assess and counteract these deficits and problems, including computerized tests and physical exercise devices. It is yet unknown how the brain will adapt to long-term space travel to the asteroids, Mars and beyond. This work represents a comprehensive review of the current knowledge and future challenges of cognitive neuroscience in space from simulations and analog missions to low Earth orbit and beyond. PMID:25370373

  17. Cognitive neuroscience in space.

    PubMed

    De la Torre, Gabriel G

    2014-01-01

    Humans are the most adaptable species on this planet, able to live in vastly different environments on Earth. Space represents the ultimate frontier and a true challenge to human adaptive capabilities. As a group, astronauts and cosmonauts are selected for their ability to work in the highly perilous environment of space, giving their best. Terrestrial research has shown that human cognitive and perceptual motor performances deteriorate under stress. We would expect to observe these effects in space, which currently represents an exceptionally stressful environment for humans. Understanding the neurocognitive and neuropsychological parameters influencing space flight is of high relevance to neuroscientists, as well as psychologists. Many of the environmental characteristics specific to space missions, some of which are also present in space flight simulations, may affect neurocognitive performance. Previous work in space has shown that various psychomotor functions degrade during space flight, including central postural functions, the speed and accuracy of aimed movements, internal timekeeping, attentional processes, sensing of limb position and the central management of concurrent tasks. Other factors that might affect neurocognitive performance in space are illness, injury, toxic exposure, decompression accidents, medication side effects and excessive exposure to radiation. Different tools have been developed to assess and counteract these deficits and problems, including computerized tests and physical exercise devices. It is yet unknown how the brain will adapt to long-term space travel to the asteroids, Mars and beyond. This work represents a comprehensive review of the current knowledge and future challenges of cognitive neuroscience in space from simulations and analog missions to low Earth orbit and beyond. PMID:25370373

  18. Displays in space.

    PubMed

    Colford, Nicholas

    2002-04-01

    This chapter describes the human and environmental factors that dictate the way that displays must be designed for, and used in space. A brief history of the evolution of such display systems covers developments from the Mercury rockets to the International Space Station. PMID:12744260

  19. Commercialization of space activities

    Microsoft Academic Search

    Hanneke L. van Traa-Engelman

    1996-01-01

    Commercialization of space activities requires a legal framework for private investors and entrepreneurs in order to promote and develop this sector of industry into a fully-fledged commercial enterprise. Apart from the already existing international public legal framework of space law, rules should be created to provide a level playing field for all interested parties. These rules should point to transparency

  20. Commercialization of space

    Microsoft Academic Search

    J. T. Rose; B. A. Stone

    1988-01-01

    Space-commercialization activities are grouped into five categories: private sector development from existing technology for private sector use; pure privatization; private sector development for US government use; private sector development from novel technology for private sector use; and, finally, full commercialization. The authors define the commercialization of space categories and highlight the key issues in each. A description of key NASA

  1. Law in Outer Space.

    ERIC Educational Resources Information Center

    Schmidt, William G.

    1997-01-01

    Provides an overview of the current practice and fascinating future of legal issues involved in outer space exploration and colonization. Current space law, by necessity, addresses broad principles rather than specific incidents. Nonetheless, it covers a variety of issues including commercial development, rescue agreements, object registration,…

  2. Space Radiation Risk Assessment

    Microsoft Academic Search

    E. Blakely

    2006-01-01

    Evaluation of potential health effects from radiation exposure during and after deep space travel is important for the future of manned missions To date manned missions have been limited to near-Earth orbits with the moon our farthest distance from earth Historical space radiation career exposures for astronauts from all NASA Missions show that early missions involved total exposures of less

  3. Dirichlet Spaces Applications

    E-print Network

    Bielefeld, University of

    for fractional Sobolev spaces over Wiener spaces Tuesday, 11th (Bonn) 11.00 -- 11.50 M. Fukushima On a singular asymptotics of transition probabilities in infinite dimensions Coffee break 16.00 -- 16.50 W. Hoh Some results

  4. Woodward Paths: Motorizing Space

    Microsoft Academic Search

    Jeff Rice

    2009-01-01

    This essay takes up the call for a rhetoric of distributed space by proposing a folksonomic rhetoric. Folksonomies, systems in which users may name any object, space, idea, or image any name they want, offer technical communicators new possibilities for how they work in network environments. As a way to explore the possibility of a folksonomic rhetoric, this essay examines

  5. How many peripersonal spaces?

    PubMed

    de Vignemont, F; Iannetti, G D

    2015-04-01

    Several studies in humans and non-human primates have explored and characterised the features of the cortical representation of the portion of space immediately surrounding the body – the peripersonal space. In this paper we ask the following question: is it legitimate to assume that there is a single representation of peripersonal space? This issue has rarely been addressed in the literature, leading to much confusion, especially when one compares results reported in social psychology and in cognitive neuroscience. Indeed, studies in both fields explore and refer to more or less the same portion of space, but the terminology used to describe it differs greatly. Therefore, the definition of this portion of space immediately surrounding the body has remained quite vague, allowing for many variations. Here, we propose a dual model of peripersonal space, based on a clear functional distinction between bodily protection and goal-directed action. We argue that the two functions of peripersonal space require distinct sensory and motor processes that obey different principles. Furthermore, we highlight that the effects of anxiety and tool use on peripersonal space provide empirical support to our distinction. PMID:25448854

  6. AB Space Engine

    Microsoft Academic Search

    Alexander Bolonkin

    2008-01-01

    On 4 January 2007 the author published the article Wireless Transfer of Electricity in Outer Space in http:\\/\\/arxiv.org wherein he offered and researched a new revolutionary method of transferring electric energy in space. In that same article, he offered a new engine which produces a large thrust without throwing away large amounts of reaction mass (unlike the conventional rocket engine).

  7. AB Space Engine

    E-print Network

    Bolonkin, Alexander

    2008-01-01

    On 4 January 2007 the author published the article Wireless Transfer of Electricity in Outer Space in http://arxiv.org wherein he offered and researched a new revolutionary method of transferring electric energy in space. In that same article, he offered a new engine which produces a large thrust without throwing away large amounts of reaction mass (unlike the conventional rocket engine). In the current article, the author develops the theory of this kind of impulse engine and computes a sample project which shows the big possibilities opened by this new AB-Space Engine. The AB-Space Engine gets the energy from ground-mounted power; a planet electric station can transfer electricity up to 1000 millions (and more) of kilometers by plasma wires. Author shows that AB-Space Engine can produce thrust of 10 tons (and more). That can accelerate a space ship to some thousands of kilometers/second. AB-Space Engine has a staggering specific impulse owing to the very small mass expended. The AB-Space Engine reacts not b...

  8. Space Weather CD

    NSDL National Science Digital Library

    2013-04-10

    This is a software package about space weather: what it is and what it does in space and here on Earth. The disc includes software that displays movies and images of the aurora and of the Sun in various wavelengths from the ground and from orbiting NASA spacecraft; a tutorial about what space weather is and how the aurora is formed; and more. Users will also find real-time space weather conditions from current satellite missions and can download the latest data without leaving the Space Weather application. A TicTacToe game is also included that tests space weather knowledge. The disc contains many other Space Weather resources, programs, sounds, and games for use at home or school, and there are several educational websites included in full on the disc for offline viewing. In addition there is an exhaustive list of links to a variety of space weather resources available online. The disc is available for free from a number of sites if downloaded.

  9. Prediction in Orlicz spaces

    Microsoft Academic Search

    R. B. Darst; D. A. Legg; D. W. Townsend

    1981-01-01

    In this paper, we investigate the prediction (or best approximation) operator from a uniformly convex real Orlicz space to a subset of s-lattice measurable functions. In particular, a counterexample to the monotoncity property, which holds in Lp spaces, is given. Also, a sufficient condition for monotonicity to hold is given. Finally, nested s-lattices, as occur in isotonic regression, are considered.

  10. Optical space communications

    Microsoft Academic Search

    Vincent W. S. Chan

    2000-01-01

    Optical space communications is on the verge of becoming a reality. It will be a key building block for wide-area space data networks of the future. We discuss the critical technology and architecture issues to be addressed for the realization of these systems, and present examples of high level designs. Design methodologies treating these as complex engineering systems, and the

  11. Language, Gesture, and Space.

    ERIC Educational Resources Information Center

    Emmorey, Karen, Ed.; Reilly, Judy S., Ed.

    A collection of papers addresses a variety of issues regarding the nature and structure of sign language, gesture, and gesture systems. Articles include: "Theoretical Issues Relating Language, Gesture, and Space: An Overview" (Karen Emmorey, Judy S. Reilly); "Real, Surrogate, and Token Space: Grammatical Consequences in ASL American Sign Language"…

  12. Solar space vehicle

    SciTech Connect

    Lee, R.E.

    1982-10-19

    This invention relates to space vehicle where solar energy is used to generate steam, which in turn, propels the vehicle in space. A copper boiler is provided and a novel solar radiation condensing means is used to focus the sunlight on said boiler. Steam generated in said boiler is exhausted to the environment to provide a thrust for the vehicle.

  13. Temporal Scale Spaces

    Microsoft Academic Search

    Daniel Fagerström

    2005-01-01

    In this paper we discuss how to define a scale space suitable for temporal measurements. We argue that such a temporal scale space should possess the properties of: temporal causality, linearity, continuity, positivity, recursitivity as well as translational and scaling covariance. It is shown that these requirements imply a one parameter family of con- volution kernels. Furthermore it is shown

  14. Emergency medicine in space

    Microsoft Academic Search

    Lowan H. Stewart; Donald Trunkey; G. Steve Rebagliati

    2007-01-01

    Recent events, including the development of space tourism and commercial spaceflight, have increased the need for specialists in space medicine. With increased duration of missions and distance from Earth, medical and surgical events will become inevitable. Ground-based medical support will no longer be adequate when return to Earth is not an option. Pending the inclusion of sub-specialists, clinical skills and

  15. A search space \\

    Microsoft Academic Search

    Daniel Cosmin Porumbel; Jin-Kao Hao; Pascale Kuntz

    2010-01-01

    We present a search space analysis and its application in improving local search algorithms for the graph coloring problem. Using a classical distance measure be- tween colorings, we introduce the following clustering hypothesis: the high quality solutions are not randomly scattered in the search space, but rather grouped in clusters within spheres of specific diameter. We first provide intuitive evidence

  16. Living in Space

    NSDL National Science Digital Library

    NASA

    2007-12-12

    NASA's Living in Space Web site allows kids of all ages the opportunity to learn how astronauts cope with zero gravity conditions in space. Everything from eating, dressing, working, and having fun is explained through descriptions, photographs, movies, audio files, and more.

  17. Space station executive summary

    NASA Technical Reports Server (NTRS)

    1972-01-01

    An executive summary of the modular space station study is presented. The subjects discussed are: (1) design characteristics, (2) experiment program, (3) operations, (4) program description, and (5) research implications. The modular space station is considered a candidate payload for the low cost shuttle transportation system.

  18. Space and Atmospheric Environments

    NASA Technical Reports Server (NTRS)

    Barth, Janet L.; Day, John H. (Technical Monitor)

    2002-01-01

    This viewgraph presentation provides information on space environments and the protection of materials and structures from their harsh conditions. Space environments are complex, and the complexity of spacecraft systems is increasing. Design accommodation must be realistic. Environmental problems can be limited at low cost relative to spacecraft cost.

  19. Cryocoolers for Space

    NASA Technical Reports Server (NTRS)

    Castles, Stephen

    2000-01-01

    This paper presents Cryocoolers for Space in viewgraph form. The topics include: 1) U.S. Cryocoolers for 4 to 6 Kelvin; 2) Turbo Brayton Cryocooler-Features; 3) HST/NICMOS (Hubble Space Telescope/Near Infrared Camera and Multiobject Spectrometer) 75 Kelvin Cryocooler; 4) Turbo-Brayton Cryocooler-NGST Design; and 5) Two-stage Sorption J-T Cryocooler.

  20. Latest Space Shuttle News

    NSDL National Science Digital Library

    2002-01-01

    This site from NASA offers the latest news on the space shuttle program. It features a variety of articles on the program. Links to other sites on the shuttle program provide provide resources such as posters, educational materials and interactive resources. Users can use the site to learn more about the most recent space shuttle missions or any of the past missions.

  1. Space charge stopband correction

    SciTech Connect

    Huang, Xiaobiao; /Fermilab /Indiana U.; Lee, S.Y.; /Indiana U.

    2005-09-01

    It is speculated that the space charge effect cause beam emittance growth through the resonant envelope oscillation. Based on this theory, we propose an approach, called space charge stopband correction, to reduce such emittance growth by compensation of the half-integer stopband width of the resonant oscillation. It is illustrated with the Fermilab Booster model.

  2. Solar space vehicle

    Microsoft Academic Search

    1982-01-01

    This invention relates to space vehicle where solar energy is used to generate steam, which in turn, propels the vehicle in space. A copper boiler is provided and a novel solar radiation condensing means is used to focus the sunlight on said boiler. Steam generated in said boiler is exhausted to the environment to provide a thrust for the vehicle.

  3. Space Mathematics Website

    NSDL National Science Digital Library

    This Website contains over 200 authentic math problems that cover solar physics, space physics, radiation dosimetry, and the human impacts of space weather. The problems range from pre-algebra to calculus and span the math skills appropriate for grade 8-12 students. The problems are taken from authentic applications of arithmetic, graph analysis, pre-algebra, and algebra.

  4. MEMS for space

    Microsoft Academic Search

    N. F. de Rooij; S. Gautsch; D. Briand; C. Marxer; G. Mileti; W. Noell; H. Shea; U. Staufer; B. van der Schoot

    2009-01-01

    Future space exploration will emphasize on cost effectiveness and highly focused mission objectives. Missions costs are directly proportional to its total weight, thus, the trend will be to replace bulky and heavy components of space carriers, communication and navigation platforms and of scientific payloads. MEMS devices are ideally suited to replace several of these components in the future, first by

  5. Space sciences - Keynote address

    NASA Technical Reports Server (NTRS)

    Alexander, Joseph K.

    1990-01-01

    The present status and projected future developments of the NASA Space Science and Applications Program are addressed. Emphasis is given to biochemistry experiments that are planned for the Space Station. Projects for the late 1990s which will study the sun, the earth's magnetosphere, and the geosphere are briefly discussed.

  6. NASA's Space Visualization Studio

    NSDL National Science Digital Library

    The mission of the Scientific Visualization Studio is to facilitate scientific inquiry and outreach within NASA programs through visualization. To that end, the SVS works closely with scientists in the creation of visualization products, systems, and processes in order to promote a greater understanding of Earth and Space Science research activities at Goddard Space Flight Center and within the NASA research community.

  7. Space Shuttle news reference

    NASA Technical Reports Server (NTRS)

    1981-01-01

    A detailed description of the space shuttle vehicle and associated subsystems is given. Space transportation system propulsion, power generation, environmental control and life support system and avionics are among the topics. Also, orbiter crew accommodations and equipment, mission operations and support, and flight crew complement and crew training are addressed.

  8. Dr. Massimo Space Telescope

    E-print Network

    Zanibbi, Richard

    Dr. Massimo Robberto Space Telescope Science Institute Massimo Robberto received in 1989 his Ph/VLT telescopes. In 1995 he joined the Max Planck Institutein Heidelberg to lead the construction of a new IR camera for the UKIRT telescope in Mauna Kea, Hawaii. In 1999 he moved to the European Space Agency

  9. NATIONAL AERONAUTICS SPACE ADMINISTRATION

    E-print Network

    Ginzel, Matthew

    NATIONAL AERONAUTICS AND SPACE ADMINISTRATION ********** GUIDEBOOK FOR PROPOSERS RESPONDING. Appendix E.1.2 has been revised as follows: E.1.2 Assurance of Compliance with the National Aeronautics and Space Administration Regulations Pursuant to Nondiscrimination in Federally Assisted Programs "The

  10. Leo space plasma interactions

    NASA Technical Reports Server (NTRS)

    Ferguson, Dale C.

    1991-01-01

    Photovoltaic arrays interact with the low earth orbit (LEO) space plasma in two fundamentally different ways. One way is the steady collection of current from the plasma onto exposed conductors and semiconductors. The relative currents collected by different parts of the array will then determine the floating potential of the spacecraft. In addition, these steady state collected currents may lead to sputtering or heating of the array by the ions or electrons collected, respectively. The second kind of interaction is the short time scale arc into the space plasma, which may deplete the array and/or spacecraft of stored charge, damage solar cells, and produce EMI. Such arcs only occur at high negative potentials relative to the space plasma potential, and depend on the steady state ion currents being collected. New high voltage solar arrays being incorporated into advanced spacecraft and space platforms may be endangered by these plasma interactions. Recent advances in laboratory testing and current collection modeling promise the capability of controlling, and perhaps even using, these space plasma interactions to enable design of reliable high voltage space power systems. Some of the new results may have an impact on solar cell spacing and/or coverslide design. Planned space flight experiments are necessary to confirm the models of high voltage solar array plasma interactions. Finally, computerized, integrated plasma interactions design tools are being constructed to place plasma interactions models into the hands of the spacecraft designer.

  11. Geometry of face space

    Microsoft Academic Search

    Lawrence Sirovich; Marsha Meytlis

    The geometrical character of face space is investigated, and is analyzed within the framework of eigenface decompositions. To deal with the sparse data problem, which occurs when not enough data is present to fill the space, we construct and test a range of probabilistic models. A key tool in this investigation is the decomposition of the eigenfaces representation of face

  12. Space applications - Another wingman

    Microsoft Academic Search

    James O. Hale

    1992-01-01

    The paper suggests some ways in which the Air Force Space Command, working with other Air Force major commands, will increase the war fighter's comfort level with - and ability to employ - space systems. It is recommended that the emphasis should be focused to provide tactical information including weather, communications, navigation, and inputs to improve situation awareness and targeting

  13. The Deep Space Network

    NASA Technical Reports Server (NTRS)

    1979-01-01

    Deep Space Network progress in flight project support, tracking and data acquisition, research and technology, network engineering, hardware and software implementation, and operations is cited. Topics covered include: tracking and ground based navigation; spacecraft/ground communication; station control and operations technology; ground communications; and deep space stations.

  14. Space Elevator: Stability

    Microsoft Academic Search

    Lubos Perek

    2008-01-01

    Many papers have been published on engineering and economic aspects of the Space Elevator. The Elevator, however, is a very special and unusual astronomical body. Its behavior in space is affected not only by the attraction of the Earth and by the “centrifugal force” but also by the attraction of the Sun and the Moon, by the detailed shape of

  15. Decompositions involving Anick's spaces

    E-print Network

    Gray, Brayton

    2008-01-01

    Recently Stephen Theriault and I found an elementary construction of Anick's spaces and proved their main properties(arXiv:0710.1024).In this work the fundamental fibration is decomposed. This is useful in studying maps out of Anick's spaces and will be needed in order to determine it's universal properties.

  16. Stereo images from space

    Microsoft Academic Search

    Massimo Sabbatini; Maximilien J. Collon; Gianfranco Visentin

    2008-01-01

    The Erasmus Recording Binocular (ERB1) was the first fully digital stereo camera used on the International Space Station. One year after its first utilisation, the results and feedback collected with various audiences have convinced us to continue exploiting the outreach potential of such media, with its unique capability to bring space down to earth, to share the feeling of weightlessness

  17. Integrating National Space Visions

    NASA Technical Reports Server (NTRS)

    Sherwood, Brent

    2006-01-01

    This paper examines value proposition assumptions for various models nations may use to justify, shape, and guide their space programs. Nations organize major societal investments like space programs to actualize national visions represented by leaders as investments in the public good. The paper defines nine 'vision drivers' that circumscribe the motivations evidently underpinning national space programs. It then describes 19 fundamental space activity objectives (eight extant and eleven prospective) that nations already do or could in the future use to actualize the visions they select. Finally the paper presents four contrasting models of engagement among nations, and compares these models to assess realistic pounds on the pace of human progress in space over the coming decades. The conclusion is that orthogonal engagement, albeit unlikely because it is unprecedented, would yield the most robust and rapid global progress.

  18. Space Experiment Module (SEM)

    NASA Technical Reports Server (NTRS)

    Brodell, Charles L.

    1999-01-01

    The Space Experiment Module (SEM) Program is an education initiative sponsored by the National Aeronautics and Space Administration (NASA) Shuttle Small Payloads Project. The program provides nationwide educational access to space for Kindergarten through University level students. The SEM program focuses on the science of zero-gravity and microgravity. Within the program, NASA provides small containers or "modules" for students to fly experiments on the Space Shuttle. The experiments are created, designed, built, and implemented by students with teacher and/or mentor guidance. Student experiment modules are flown in a "carrier" which resides in the cargo bay of the Space Shuttle. The carrier supplies power to, and the means to control and collect data from each experiment.

  19. Teaching With Space

    NSDL National Science Digital Library

    1969-12-31

    Teaching With Space is intended as a resource for teachers who want to introduce their students to space science and technology. A brief, free registration is required to access the educational modules, of which there are five in all. Among the topics are such elements as aerospace technology, "human exploration and development of space," and methods of teaching with technology. Each of the modules begins with a short quiz to assess the user's familiarity with the subject. One section contains slide presentations about the International Space Station, while others provide educational insights into various space-related concepts. Because of the amount of information presented on this site, anyone, not just teachers, could benefit from the material.

  20. Plants in Space

    NSDL National Science Digital Library

    2011-12-21

    The BioEd Online website is giving interested parties everywhere the opportunity to learn from plants in space. Created in partnership with the National Space Biomedical Research Institute and BioServe Space Technologies of the University of Colorado, the project brings together plants from the International Space Station and plants grown by young people in their respective classrooms. The videos and teacher's guides here will let students perform their own experiments in the classroom based on data from space. Visitors will find PowerPoint presentations here for use in the classroom, along with videos of the plants in different states of germination. The site is rounded out by detailed information about this type of scientific investigation and the National Science Education Standards.

  1. Plants in Space

    NSDL National Science Digital Library

    The BioEd Online website is giving interested parties everywhere the opportunity to learn from plants in space. Created in partnership with the National Space Biomedical Research Institute and BioServe Space Technologies of the University of Colorado, the project brings together plants from the International Space Station and plants grown by young people in their respective classrooms. The videos and teacher's guides here will let students perform their own experiments in the classroom based on data from space. Visitors will find Power-Point presentations here for use in the classroom, along with videos of the plants in different states of germination. The site is rounded out by detailed information about this type of scientific investigation and the National Science Education Standards.

  2. Wireless Communications in Space

    NASA Technical Reports Server (NTRS)

    2004-01-01

    In 1992, NASA and the U.S. Department of Defense jointly commissioned the research and development of a technology solution to address the challenges and requirements of communicating with their spacecraft. The project yielded an international consortium composed of representatives from the space science community, industry, and academia. This group of experts developed a broad suite of protocols specifically designed for space-based communications, known today as Space Communications Protocol Standards (SCPS). Having been internationally standardized by the Consultative Committee on Space Data Systems and the International Standards Organization, SCPS is distributed as open source technology by NASA s Jet Propulsion Laboratory (JPL). The protocols are used for every national space mission that takes place today.

  3. Space and Time

    NSDL National Science Digital Library

    This fun Web site is part of OLogy, where kids can collect virtual trading cards and create projects with them. Here, they are introduced to space and time with six engaging and kid-friendly areas: Welcome to the Fourth Dimension, which looks at how time is needed to describe where you are in the fourth dimension; It's All Relative, an explanation of how time and space are different depending on your frame of reference; Mass Appeal, which uses the example of an elephant on a page of paper to explain how the Sun's mass causes space and time to bend; You Light Up My Life, how Arthur Eddington proved that Einstein's light-bending prediction was right; Everyday Einstein: Black Holes, an overview of these "bottomless dimples in space." and Time Travel Kit, a look at how the faster you move in space, the slower you move in time.

  4. Lubrication of space systems

    NASA Technical Reports Server (NTRS)

    Fusaro, Robert L.

    1994-01-01

    NASA has many high-technology programs plannned for the future, such as the space station, Mission to Planet Earth (a series of Earth-observing satellites), space telescopes, and planetary orbiters. These missions will involve advanced mechanical moving components, space mechanisms that will need wear protection and lubrication. The tribology practices used in space today are primarily based on a technology that is more than 20 years old. The question is the following: Is this technology base good enough to meet the needs of these future long-duration NASA missions? This paper examines NASA's future space missions, how mechanisms are currently lubricated, some of the mechanism and tribology challenges that may be encountered in future missions, and some potential solutions to these future challenges.

  5. Hubble Space Telescope

    NASA Astrophysics Data System (ADS)

    The Space Telescope, scheduled for launch aboard the Space Shuttle in 1986, has been renamed the Edwin P. Hubble Space Telescope, the National Aeronautics and Space Administration (NASA) announced. The orbiting optical astronomical observatory will carry a 2.4-m mirror and five scientific instruments that will be able to look into space 7 times farther than any ground-based observatory; NASA expects the resolution of the resulting images to be 10-20 times better than images from ground-based instruments.Hubble probably is best known for his discovery, with colleague Milton Humason, that the universe is expanding. Hubble confirmed that the faint, spiral nebulae viewed through the Mount Wilson Observatory's Hooker Telescope were distant systems receding from us at velocities proportional to their distances. Hubble was a staff member at Carnegie Institution's Mount Wilson Observatory near Pasadena, Calif., from 1919 until his death in 1953.

  6. Space Shuttle Drawing

    NASA Technical Reports Server (NTRS)

    2004-01-01

    The Apollo program demonstrated that men could travel into space, perform useful tasks there, and return safely to Earth. But space had to be more accessible. This led to the development of the Space Shuttle. The Shuttle's major components are the orbiter spacecraft; the three main engines, with a combined thrust of more than 1.2 million pounds; the huge external tank (ET) that feeds the liquid hydrogen fuel and liquid oxygen oxidizer to the three main engines; and the two solid rocket boosters (SRBs), with their combined thrust of some 5.8 million pounds, that provide most of the power for the first two minutes of flight. Crucially involved with the Space Shuttle program virtually from its inception, the Marshall Space Flight Center (MSFC) played a leading role in the design, development, testing, and fabrication of many major Shuttle propulsion components.

  7. Space station thermal control surfaces. [space radiators

    NASA Technical Reports Server (NTRS)

    Maag, C. R.; Millard, J. M.; Jeffery, J. A.; Scott, R. R.

    1979-01-01

    Mission planning documents were used to analyze the radiator design and thermal control surface requirements for both space station and 25-kW power module, to analyze the missions, and to determine the thermal control technology needed to satisfy both sets of requirements. Parameters such as thermal control coating degradation, vehicle attitude, self eclipsing, variation in solar constant, albedo, and Earth emission are considered. Four computer programs were developed which provide a preliminary design and evaluation tool for active radiator systems in LEO and GEO. Two programs were developed as general programs for space station analysis. Both types of programs find the radiator-flow solution and evaluate external heat loads in the same way. Fortran listings are included.

  8. Kennedy Space Center - "America's Gateway to Space"

    NASA Technical Reports Server (NTRS)

    Petro, Janet; Chevalier, Mary Ann; Hurst, Chery

    2011-01-01

    KSC fits into the overall NASA vision and mission by moving forward so that what we do and learn will benefit all here on Earth. In January of last year, KSC revised its Mission and Vision statements to articulate our identity as we align with this new direction the Agency is heading. Currently KSC is endeavoring to form partnerships with industry, , Government, and academia, utilizing institutional assets and technical capabilities to support current and future m!issions. With a goal of safe, low-cost, and readily available access to space, KSC seeks to leverage emerging industries to initiate development of a new space launch system, oversee the development of a multipurpose crew vehicle, and assist with the efficient and timely evolution of commercial crew transportation capabilities. At the same time, KSC is pursuing modernizing the Center's infrastructure and creating a multi-user launch complex with increased onsite processing and integration capabilities.

  9. The space simulation facilities at IAL SPACE

    NASA Technical Reports Server (NTRS)

    Henrist, M.; Cucchiaro, A.; Domken, I.; Macau, J. P.

    1990-01-01

    The thermal vacuum facilities of IAL SPACE were tailored for testing of the ESA payloads. They were progressively upgraded for cryogenic payloads including 4 K (liquid helium temperature) experiments. A detailed review of the three vacuum chambers, ranging from 1.5 to 5 m diameter, is presented including the corresponding capabilities in the vacuum, thermal, and optical fields. The various aspects of cleanliness, product assurance, and quality control are also presented.

  10. Overview of Space Business Space & Integrated Defense Systems

    E-print Network

    40 years, covering civil/commercial space business, defense related space business and defenseOverview of Space Business Space & Integrated Defense Systems Mitsubishi Corporation August 26 in Rio de Janeiro and Belo Horizonte #12;MC's Space Business Involved with aerospace business more than

  11. National Aeronautics and Space Administration Commercial Space Committee

    E-print Network

    Waliser, Duane E.

    National Aeronautics and Space Administration Commercial Space Committee of the NASA Advisory forecast project was funded jointly by the Federal Aviation Administration (FAA) and Space Florida, which __________________________________ ________________________________________ Thomas W. Rathjen Patti Grace Smith Executive Secretary Chair Commercial Space Committee Commercial Space

  12. National Aeronautics and Space Administration Space Life and Physical Sciences

    E-print Network

    Waliser, Duane E.

    National Aeronautics and Space Administration Space Life and Physical Sciences Status Briefing PRESIDENT'S BUDGET REQUEST SUMMARY National Aeronautics and Space Administration 6 #12;2014 Space Operations Budget National Aeronautics and Space Administration FY 2014 PRESIDENT'S BUDGET REQUEST SUMMARY 7 #12

  13. National Aeronautics and Space Administration Space Shuttle Transition and Retirement

    E-print Network

    National Aeronautics and Space Administration NASAfacts Space Shuttle Transition and Retirement.S. Space and Rocket Center of Huntsville,Ala., National Air and Space Museum in Washington, and Evergreen Three NASA space shuttles are undergoing an extensive transition and retirement (T&R) phase

  14. National Aeronautics and Space Administration Stennis Space Center

    E-print Network

    National Aeronautics and Space Administration Stennis Space Center NASA's John C. Stennis Space organizations and numerous technology-based companies. RESIDENT AGENCIES National Aeronautics and Space Administration John C. Stennis Space Center www.nasa.gov/centers/stennis 228-688-3333 NASA Shared Services Center

  15. Capacity Building in Space Law and Space Policy

    Microsoft Academic Search

    Ram Jakhu

    2008-01-01

    A high level of expertise in space policy and law is required to keep pace with expansion of space activities (including space industry). Space activities are generally referred to those activities that are carried out with the use of several technologies for exploration and utilization of outer space often for scientific, economic and social proposes within international and national policy

  16. Capacity building in space law and space policy

    Microsoft Academic Search

    Ram Jakhu

    2009-01-01

    A high level of expertise in space policy and law is required to initiate and keep pace with the expansion of space activities, including those undertaken by the private space industry. Space activities generally refer to those undertakings that are carried out with the use of several technologies for the exploration and utilization of outer space often for scientific, military,

  17. Space Radiation Protection, Space Weather, and Exploration

    NASA Technical Reports Server (NTRS)

    Zapp, Neal; Rutledge, R.; Semones, E. J.; Johnson, A. S.; Guetersloh, S.; Fry, D.; Stoffle, N.; Lee, K.

    2008-01-01

    Management of crew exposure to radiation is a major concern for manned spaceflight -- and will be even more important for the modern concept of longer-duration exploration. The inherent protection afforded to astronauts by the magnetic field of the Earth in Low Earth Orbit (LEO) makes operations on the space shuttle or space station very different from operations during an exploration mission. In order to experience significant radiation-derived Loss of Mission (LOM) or Loss of Crew (LOC) risk for LEO operations, one is almost driven to dictate extreme duration or to dictate an extreme sequence of solar activity. Outside of the geo-magnetosphere, however, this scenario changes dramatically. Exposures to the same event on the ISS and on the surface of the Moon may differ by multiple orders of magnitude. This change in magnitude, coupled with the logistical constraints present in implementing any practical operational mitigation make situational awareness with regard to space weather a limiting factor for our ability to conduct exploration operations. With these differences in risk to crew, vehicle and mission in mind, we present the status of the efforts currently underway as the required development to enable exploration operations. The changes in the operating environment as crewed operations begin to stretch away from the Earth are changing the way we think about the lines between "research" and "operations". The real, practical work to enable a permanent human presence away from Earth has already begun.

  18. The Rocks From Space 'Space Safari

    NASA Astrophysics Data System (ADS)

    Pearson, Victoria; Brooks, Val

    2010-05-01

    We describe an integrated online science programme incorporating Moodle virtual learning environments (VLEs) and Elluminate Live! virtual classrooms. The "Space Safari" was run as part of the Rocks From Space (RFS) programme hosted at The Open University (OU) and in partnership with Stockton City Learning Centre (SCLC). Schools used these resources for direct science teaching or to incorporate them into the wider curriculum (arts/literature etc), after which they produce an output. Emphasis was on providing links between schools and scientists within the higher education sector. Live sessions with experts via Elluminate Live! were held regularly, including sessions with NASA scientists and astronomers in Mallorca. Teachers and students have used Space Safari resources as part of the school science curriculum and to develop key skills and additional curriculum skills. They have also used it for informal (forums, online discussions) opportunities to engage with science. Over 3 years of the project, over 1500 students have engaged, with the project. The use of virtual classrooms enabled direct interaction with many students; one session alone involved over 100 students. This project is now hosted on the eTwinning portal to enable sustainability and widen access.

  19. The Swedish space programme

    NASA Astrophysics Data System (ADS)

    Helger, Arne

    The Swedish National Space Board (SNSB) under the Ministry of Industry is the central governmental agency responsible for the goverment-funded Swedish national and international space and remote sensing activities. The technical implementation is mainly contracted by the Board to the state-owned Swedish Space Corporation (SSC). International cooperation is a cornerstone in the Swedish space activities, absorbing more than 80% of the total national budget. Within ESA, Sweden participates in practically all infrastructure and applications programs. Basic research, mainly concentrated to the near earth space physics, microgravity and remote sensing are important elements in the Swedish space program. Sweden participates in the French Spot program. At Esrange, data reception, and satellite control, and tracking, telemetry command (TT&C) are performed for many international satellite projects. An SSC subsidiary, SATELLITBILD, is archiving, processing and distributing remote sensing data worldwide. The National Space Development Agency of Japan (NASDA) has established a portable TT&C station for JERS-1 at Esrange, Kiruna. A center for international research on the ozone problem has been established at Esrange and Kiruna. A new sounding rocket for 15 minutes of microgravity research, MAXUS, has been developed by SSC in cooperation with Germany. A national scientific satellite, FREJA, is planned to be launched late 1992.

  20. Fundamentals of Space Systems

    NASA Astrophysics Data System (ADS)

    Pisacane, Vincent L.

    2005-06-01

    Fundamentals of Space Systems was developed to satisfy two objectives: the first is to provide a text suitable for use in an advanced undergraduate or beginning graduate course in both space systems engineering and space system design. The second is to be a primer and reference book for space professionals wishing to broaden their capabilities to develop, manage the development, or operate space systems. The authors of the individual chapters are practicing engineers that have had extensive experience in developing sophisticated experimental and operational spacecraft systems in addition to having experience teaching the subject material. The text presents the fundamentals of all the subsystems of a spacecraft missions and includes illustrative examples drawn from actual experience to enhance the learning experience. It included a chapter on each of the relevant major disciplines and subsystems including space systems engineering, space environment, astrodynamics, propulsion and flight mechanics, attitude determination and control, power systems, thermal control, configuration management and structures, communications, command and telemetry, data processing, embedded flight software, survuvability and reliability, integration and test, mission operations, and the initial conceptual design of a typical small spacecraft mission.

  1. Space Update CD

    NSDL National Science Digital Library

    2013-04-11

    This is an interactive, real-time display system of space science images and data designed for museums and schools. The program displays hundreds of images and movies from space science research, all documented, with web references of how to find out more information. The materials also include a large number of space science educational activities. The software is available for purchase. Full-screen versions without support files are available for download but require a registration number after a 30-day demo period.

  2. Space station propulsion technology

    NASA Technical Reports Server (NTRS)

    Norman, A. M.; Briley, G. L.; Evans, S. A.

    1987-01-01

    The objectives of this program are to provide a demonstration of hydrogen/oxygen propulsion technology readiness for the initial operational capability (IOC) space station application, specifically gaseous hydrogen/oxygen and warm hydrogen thruster concepts, and to establish a means for evolving from the IOC space station propulsion system (SSPS) to that required to support and interface with advanced station functions. These objectives were met by analytical studies and by furnishing a propulsion test bed to the Marshall Space Flight Center for testing.

  3. Diffusion on $?$-Minkowski space

    E-print Network

    Michele Arzano; Tomasz Trzesniewski

    2014-06-24

    We study the spectral dimension associated with diffusion processes on Euclidean $\\kappa$-Minkowski space. We start by describing a geometric construction of the "Euclidean" momentum group manifold related to $\\kappa$-Minkowski space. On such space we identify various candidate Laplacian functions, i.e. deformed Casimir invariants, and calculate the corresponding spectral dimension for each case. The results obtained show a variety of running behaviours for the spectral dimension according to the choice of deformed Laplacian, from dimensional reduction to super-diffusion.

  4. Rocket and Space Technology

    NSDL National Science Digital Library

    Braeunig, Robert A.

    Orbital mechanics, propulsion, rocket hardware, space centers and missions are among the topics featured on Robert A. Braeunig's Rocket and space Technology page. Braeunig is a civil engineer whose hobby is learning about space flight. This page is well-researched, and all sources are credited. The text disseminates relatively simple explanations of the mechanics of rocket flight and includes definitions of important terms and black-and-white diagrams. Sample problems, tables, and formulas make the site useful to secondary educators and students. The science and mathematics behind everything from building a spacecraft to launching it are covered in this instructional site.

  5. Space Station Induced Monitoring

    NASA Technical Reports Server (NTRS)

    Spann, James F. (editor); Torr, Marsha R. (editor)

    1988-01-01

    This report contains the results of a conference convened May 10-11, 1988, to review plans for monitoring the Space Station induced environment, to recommend primary components of an induced environment monitoring package, and to make recommendations pertaining to suggested modifications of the Space Station External Contamination Control Requirements Document JSC 30426. The contents of this report are divided as Follows: Monitoring Induced Environment - Space Station Work Packages Requirements, Neutral Environment, Photon Emission Environment, Particulate Environment, Surface Deposition/Contamination; and Contamination Control Requirements.

  6. Evolution to Space

    NASA Technical Reports Server (NTRS)

    Cohen, Jacob

    2013-01-01

    This presentation will discuss recent space exploration results (LCROSS, KEPLER, etc.), increase access to space and the small and cube satellites platform as it relates to the future of space exploration. It will highlight the concept of modularization and the use of biology, and specifically synthetic biology in the future. The presentation will be a general public presentation. When speaking to a younger audience, I will discuss my background. All slides contain only public information. No technical ITAR/Export controlled material will be discussed.

  7. Space rescue considerations.

    NASA Technical Reports Server (NTRS)

    Rose, R. G.

    1972-01-01

    Basic objectives of rescue requirements are examined together with the hazards that would necessitate a space rescue. Such hazards include subsystem or component malfunction, crew illness or injury, enhanced radiation levels, fire, collisions, contamination, explosion or implosion, extravehicular hazard, meteoroid penetration, and operational errors. The space rescue requirement, in most cases, is one of accelerated crew retrieval. Escape and rescue systems are discussed, taking into consideration the space shuttle as an example of an earth-based rescue system. Other systems considered include a separable escape capsule and an orbital-based rescue system.

  8. Commercialization of space

    NASA Technical Reports Server (NTRS)

    Rose, James T.; Stone, Barbara A.

    1988-01-01

    Space-commercialization activities are grouped into five categories: private sector development from existing technology for private sector use; pure privatization; private sector development for U.S. government use; private sector development from novel technology for private sector use; and, finally, full commercialization. The commercialization of space categories is defined, and the key issues in each are highlighted. A description of key NASA actions is included for each category. It is concluded that NASA and other government agency involvement is a common thread across the spectrum of space commercialization activities.

  9. Space engine safety system

    NASA Technical Reports Server (NTRS)

    Maul, William A.; Meyer, Claudia M.

    1991-01-01

    A rocket engine safety system is designed to initiate control procedures which will minimize damage to the engine and vehicle or test stand in the event of an engine failure. This report describes the features and the implementation issues associated with rocket engine safety systems. Specific concerns of safety systems applied to a space-based engine and long duration space missions are discussed. Examples of safety system features and architectures are given from recent safety monitoring investigations conducted for the Space Shuttle Main Engine and for future liquid rocket engines. Also, a general design and implementation process for rocket engine safety systems is presented.

  10. Space Shuttle Aging Elastomers

    NASA Technical Reports Server (NTRS)

    Curtis, Cris E.

    2007-01-01

    The reusable Manned Space Shuttle has been flying into Space and returning to earth for more than 25 years. The Space Shuttle's uses various types of elastomers and they play a vital role in mission success. The Orbiter has been in service well past its design life of 10 years or 100 missions. As part of the aging vehicle assessment one question under evaluation is how the elastomers are performing. This paper will outline a strategic assessment plan, how identified problems were resolved and the integration activities between subsystems and Aging Orbiter Working Group.

  11. SpaceCube Mini

    NASA Technical Reports Server (NTRS)

    Lin, Michael; Petrick, David; Geist, Alessandro; Flatley, Thomas

    2012-01-01

    This version of the SpaceCube will be a full-fledged, onboard space processing system capable of 2500+ MIPS, and featuring a number of plug-andplay gigabit and standard interfaces, all in a condensed 3x3x3 form factor [less than 10 watts and less than 3 lb (approximately equal to 1.4 kg)]. The main processing engine is the Xilinx SIRF radiation- hardened-by-design Virtex-5 FX-130T field-programmable gate array (FPGA). Even as the SpaceCube 2.0 version (currently under test) is being targeted as the platform of choice for a number of the upcoming Earth Science Decadal Survey missions, GSFC has been contacted by customers who wish to see a system that incorporates key features of the version 2.0 architecture in an even smaller form factor. In order to fulfill that need, the SpaceCube Mini is being designed, and will be a very compact and low-power system. A similar flight system with this combination of small size, low power, low cost, adaptability, and extremely high processing power does not otherwise exist, and the SpaceCube Mini will be of tremendous benefit to GSFC and its partners. The SpaceCube Mini will utilize space-grade components. The primary processing engine of the Mini is the Xilinx Virtex-5 SIRF FX-130T radiation-hardened-by-design FPGA for critical flight applications in high-radiation environments. The Mini can also be equipped with a commercial Xilinx Virtex-5 FPGA with integrated PowerPCs for a low-cost, high-power computing platform for use in the relatively radiation- benign LEOs (low-Earth orbits). In either case, this version of the Space-Cube will weigh less than 3 pounds (.1.4 kg), conform to the CubeSat form-factor (10x10x10 cm), and will be low power (less than 10 watts for typical applications). The SpaceCube Mini will have a radiation-hardened Aeroflex FPGA for configuring and scrubbing the Xilinx FPGA by utilizing the onboard FLASH memory to store the configuration files. The FLASH memory will also be used for storing algorithm and application code for the PowerPCs and the Xilinx FPGA. In addition, it will feature highspeed DDR SDRAM (double data rate synchronous dynamic random-access memory) to store the instructions and data of active applications. This version will also feature SATA-II and Gigabit Ethernet interfaces. Furthermore, there will also be general-purpose, multi-gigabit interfaces. In addition, the system will have dozens of transceivers that can support LVDS (low-voltage differential signaling), RS-422, or SpaceWire. The SpaceCube Mini includes an I/O card that can be customized to meet the needs of each mission. This version of the SpaceCube will be designed so that multiple Minis can be networked together using SpaceWire, Ethernet, or even a custom protocol. Scalability can be provided by networking multiple SpaceCube Minis together. Rigid-Flex technology is being targeted for the construction of the SpaceCube Mini, which will make the extremely compact and low-weight design feasible. The SpaceCube Mini is designed to fit in the compact CubeSat form factor, thus allowing deployment in a new class of missions that the previous SpaceCube versions were not suited for. At the time of this reporting, engineering units should be available in the summer 2012.

  12. Commercial Space Activities at Goddard

    E-print Network

    Waliser, Duane E.

    Commercial Space Activities at Goddard Space Flight Center Chris Scolese Director, Goddard Space Flight Center #12;Commercial Space at Goddard · Goddard has been involved in Commercial Space for over 30, or the launch vehicle. ­ Rapid Spacecraft Development Office ­ Commercial Utilization of Integration & Test

  13. International Space Exploration Coordination Group

    E-print Network

    Rathbun, Julie A.

    International Space Exploration Coordination Group The Global Exploration Roadmap August 2013 #12 The Global Exploration Roadmap is being developed by space agencies participating in the International Space for collaborative space exploration missions beginning with the International Space Station (ISS) and continuing

  14. National Aeronautics and Space Administration

    E-print Network

    Rathbun, Julie A.

    ,,/ NASA National Aeronautics and Space Administration Lyndon B. Johnson Space Center Houston by the National Aeronautics and Space Administration ii Hosted by the National Academy of Sclences was prepared by the Solar System Exploration Division, Johnson Space Center, National Aeronautics and Space

  15. Current Space Law And Policy

    Microsoft Academic Search

    Maj Jane Gibson; LCDR Jeremy Powell

    Space policy defines the overarching goals and principles of the US space pro - gram. International and domestic laws and regulations, national interests, and security objectives shape the US space program. This chapter examines the inter- national and domestic legal parameters within which the United States conducts its space programs and outlines the basic tenets of US space policy. The

  16. Virginia SpaceLink Virginia Space Grant Consortium

    E-print Network

    Virginia SpaceLink Virginia Space Grant Consortium VSGC's Commonwealth STEM Industry Internship companies who wish to hire them. The Virginia Space Grant Consortium's newly established Commonwealth STEM Industry Internship Program (CSIIP)wasannouncedattheNorthernVirginiaTechnologyCoun- cil Titans

  17. Technologies. [space power sources

    NASA Technical Reports Server (NTRS)

    Brandhorst, Henry W., Jr.

    1992-01-01

    Energy technologies to meet the power requirements of future space missions are reviewed. Photovoltaic, solar dynamic, and solar thermal technologies are discussed along with techniques for energy storage and power management and distribution.

  18. Envisioning creative space

    E-print Network

    Özkâr, Mine, 1976-

    1999-01-01

    This thesis proposes a framework to articulate certain criteria in creative spatial productions such as architecture. I discuss that a conformist and unquestioning adaptation to conventional space conceptions limits ...

  19. Space tug thermal control

    NASA Technical Reports Server (NTRS)

    Ward, T. L.

    1975-01-01

    The future development of full capability Space Tug will impose strict requirements upon the thermal design. While requiring a reliable and reusable design, Space Tug must be capable of steady-state and transient thermal operation during any given mission for mission durations of up to seven days and potentially longer periods of time. Maximum flexibility and adaptability of Space Tug to the mission model requires that the vehicle operate within attitude constraints throughout any specific mission. These requirements were translated into a preliminary design study for a geostationary deploy and retrieve mission definition for Space Tug to determine the thermal control design requirements. Results of the study are discussed with emphasis given to some of the unique avenues pursued during the study, as well as the recommended thermal design configuration.

  20. Space and national security

    SciTech Connect

    Stares, P.B.

    1987-01-01

    In this timely volume, the author assesses the long-term costs and benefits of developing ASAT weapons and the feasibility of alternative policies. He examines in detail the military space programs of the United States and Soviet Union and explores the potential military uses of space. He also addresses the threats to space systems and how they can be defended, the impact of ASAT attacks in wartime, and the utility of arms control. The author concludes that current U.S. policy is both shortsighted and unbalanced in stressing ASAT development over meaningful limitations on space weaponry. He presents a list of unilateral and negotiated measures as an alternative strategy for the United States.

  1. Saving Space in China

    E-print Network

    Hacker, Randi

    2013-09-09

    Broadcast Transcript: The Chinese are geniuses at utilizing every inch of space. In a country that is historically overcrowded, this skill is important for survival. Chinese vegetable gardens are miracles of permaculture layout: small plants nestle...

  2. The deep space network

    NASA Technical Reports Server (NTRS)

    1977-01-01

    The facilities, programming system, and monitor and control system for the deep space network are described. Ongoing planetary and interplanetary flight projects are reviewed, along with tracking and ground-based navigation, communications, and network and facility engineering.

  3. Space Smackdown 101

    NASA Technical Reports Server (NTRS)

    Hasan, David A.

    2011-01-01

    Space Smackdown is a competition that involves a collaborative multi-team exercise that engages in constructive simulation of a world with simulation of vehicles deployed in that world including stand-alone and integrated missions.

  4. Kennedy Space Center

    NASA Technical Reports Server (NTRS)

    Simpkins, Patrick A.

    2010-01-01

    This slide presentation reviews the importance of the Kennedy Space Center both in terms to the economy of Florida and to spaceflight. It reviews the general NASA direction,the challenges of the coming year and the accomplishments.

  5. The deep space network

    NASA Technical Reports Server (NTRS)

    1977-01-01

    A Deep Space Network progress report is presented dealing with in flight project support, tracking and data acquisition research and technology, network engineering, hardware and software implementation, and operations.

  6. The Deep Space Network

    NASA Technical Reports Server (NTRS)

    1979-01-01

    Progress on the Deep Space Network (DSN) supporting research and technology, advanced development, engineering and implementation, and DSN operations is presented. The functions and facilities of the DSN are described.

  7. Strange Stuff in Space

    NSDL National Science Digital Library

    Roberta Johnson

    2000-07-01

    This section of the Windows to the Universe web site provides information and images about strange stuff in space including detailed information about supernovas, white dwarfs, neutron stars, black holes, quasars, gravitational lensing, and gamma ray bursters. Windows to the Universe is a user-friendly learning system pertaining to the Earth and Space sciences. The objective of this project is to develop an innovative and engaging web site that spans the Earth and Space sciences and includes a rich array of documents, including images, movies, animations, and data sets that explore the Earth and Space sciences and the historical and cultural ties between science, exploration and the human experience. Links at the top of each page allow users to navigate between beginner, intermediate and advanced levels.

  8. NOAA's Space Environment Center

    NSDL National Science Digital Library

    National Oceanic & Atmospheric Administration's (NOAA's) Space Environment Center now offers a WWW server provides today's solar weather including a current solar image, x-ray and proton plots from GOES satellites, and the latest forecast of solar-terrestial conditions.

  9. Space-Age Shades

    NASA Technical Reports Server (NTRS)

    2002-01-01

    Silhouette's Titan Minimal Art frames possess a super elasticity that ensures a slip-free fit for wearing comfort, without causing irritating pressure points. The titanium alloy used in the frames also prevents allergic reactions. This technology is available to both NASA astronauts and public consumers in either corrective eyewear or sunglass models. The only difference between the sunwear used by NASA astronauts and the commercial models is the lens. Silhouette and Dr. Keith Manuel, the "official" optometrist overseeing the NASA Space Shuttle, the International Space Station, and various other vision-related space projects, brought NASA a lens that is considerably darker (5.5 percent overall light transmittance), with a thin gold coating that offers total protection, not only against ultraviolet (UV) radiation, but also against the harmful infrared radiation in space.

  10. The deep space network

    NASA Technical Reports Server (NTRS)

    1979-01-01

    Progress is reported in flight project support, tracking and data acquisition research and technology, network engineering, hardware and software implementation, and operations. The functions and facilities of the Deep Space Network are emphasized.

  11. Notes on sexuality & space

    E-print Network

    Jacobson, Samuel Ray

    2013-01-01

    Very little has been written on sexuality in architectural scholarship. Sexuality & Space (Princeton Architectural Press, 1992) contains the proceedings of an eponymous 1990 conference at Princeton University, and was both ...

  12. Electrophoresis operations in space

    NASA Technical Reports Server (NTRS)

    Richman, D. W.

    1982-01-01

    Application of electrophoresis in space processing is described. Spaceborne experiments in areas such as biological products and FDA approved drugs are discussed. These experiments will be carried on shuttle payloads.

  13. Telescopes and space exploration

    NASA Technical Reports Server (NTRS)

    Brandt, J. C.; Maran, S. P.

    1982-01-01

    Progress in contemporary astronomy and astrophysics is shown to depend on complementary investigations with sensitive telescopes operating in several wavelength regions, some of which can be on the Earth's surface and others of which must be in space.

  14. Hubble Space Telescope Image

    NASA Technical Reports Server (NTRS)

    1998-01-01

    This photograph is a Hubble Space Telescope (HST) image of a sky full of glittering jewels. The HST peered into the Sagittarius star cloud, a narrow dust free region, providing this spectacular glimpse of a treasure chest full of stars.

  15. Serving the Space Administration

    ERIC Educational Resources Information Center

    Campbell, Jack E.; Thompson, Arthur W.

    1974-01-01

    The purpose of the current program was to establish an upward mobility program that afforded employees an opportunity to improve their credibility in job opportunity selection under the directives of the National Aeronautics and Space Administration. (Author/RK)

  16. A Nanotube Space Elevator

    NSDL National Science Digital Library

    2008-08-26

    In this video adapted from NOVA scienceNOW, find out about the discovery of a new building material, the carbon nanotube, whose physical properties could theoretically enable the creation of a 22,000-mile elevator to space.

  17. Space Borne Event Timer

    NASA Technical Reports Server (NTRS)

    Turko, B.

    1980-01-01

    The Space Borne Event Timer is a part of the NASA laser ranging system that is intended to operate aboard the Space Shuttle orbiting over California. The object is to measure, by laser ranging, the earth movement along the San Andreas fault and possibly forecast future earthquakes. A number of cube reflector targets will be placed along both sides of the fault. The ranging system aboard the Space Shuttle will fire a burst of laser pulses at each target and detect the reflected light. Time differences between pulses from the two sides of the fault will indicate earth displacements. The Space Borne Event Timer is a CAMAC compatible system that provides extremely accurate timing data and controls the operation of the ranging system. For each event the time is given in 19.53 increments from the instant of firing the laser to the instant the reflected light is received back, within a range of 130 days.

  18. The deep space network

    NASA Technical Reports Server (NTRS)

    1980-01-01

    The functions and facilities of the Deep Space Network are considered. Progress in flight project support, tracking and data acquisition research and technology, network engineering, hardware and software implementation, and operations is reported.

  19. Space Shuttle astrodynamical constants

    NASA Technical Reports Server (NTRS)

    Cockrell, B. F.; Williamson, B.

    1978-01-01

    Basic space shuttle astrodynamic constants are reported for use in mission planning and construction of ground and onboard software input loads. The data included here are provided to facilitate the use of consistent numerical values throughout the project.

  20. Geometry of imaginary spaces.

    PubMed

    Koenderink, Jan J

    2012-01-01

    "Imaginary space" is a three-dimensional visual awareness that feels different from what you experience when you open your eyes in broad daylight. Imaginary spaces are experienced when you look "into" (as distinct from "at") a picture for instance. Empirical research suggests that imaginary spaces have a tight, coherent structure, that is very different from that of three-dimensional Euclidean space. This has to be due to some constraints on psychogenesis, that is the development of awareness. I focus on the topic of how, and where, the construction of such geometrical structures, that figure prominently in one's awareness, is implemented in the brain. My overall conclusion-with notable exceptions-is that present day science has no clue. I indicate some possibly rewarding directions of research. PMID:22137938

  1. Space Station Software Issues

    NASA Technical Reports Server (NTRS)

    Voigt, S. (editor); Beskenis, S. (editor)

    1985-01-01

    Issues in the development of software for the Space Station are discussed. Software acquisition and management, software development environment, standards, information system support for software developers, and a future software advisory board are addressed.

  2. Space Station Software Recommendations

    NASA Technical Reports Server (NTRS)

    Voigt, S. (editor)

    1985-01-01

    Four panels of invited experts and NASA representatives focused on the following topics: software management, software development environment, languages, and software standards. Each panel deliberated in private, held two open sessions with audience participation, and developed recommendations for the NASA Space Station Program. The major thrusts of the recommendations were as follows: (1) The software management plan should establish policies, responsibilities, and decision points for software acquisition; (2) NASA should furnish a uniform modular software support environment and require its use for all space station software acquired (or developed); (3) The language Ada should be selected for space station software, and NASA should begin to address issues related to the effective use of Ada; and (4) The space station software standards should be selected (based upon existing standards where possible), and an organization should be identified to promulgate and enforce them. These and related recommendations are described in detail in the conference proceedings.

  3. Earth study from space

    NASA Technical Reports Server (NTRS)

    Sidorenko, A. V.

    1981-01-01

    The significance that space studies are making to all Earth sciences in the areas of geography, geodesy, cartography, geology, meteorology, oceanology, agronomy, and ecology is discussed. It is predicted that cosmonautics will result in a revolution in science and technology.

  4. The Deep Space Network

    NASA Technical Reports Server (NTRS)

    1977-01-01

    The various systems and subsystems are discussed for the Deep Space Network (DSN). A description of the DSN is presented along with mission support, program planning, facility engineering, implementation and operations.

  5. Liquid lubrication in space

    NASA Technical Reports Server (NTRS)

    Zaretsky, Erwin V.

    1990-01-01

    The requirement for long-term, reliable operation of aerospace mechanisms has, with a few exceptions, pushed the state of the art in tribology. Space mission life requirements in the early 1960s were generally 6 months to a year. The proposed U.S. space station schedule to be launched in the 1990s must be continuously usable for 10 to 20 years. Liquid lubrication systems are generally used for mission life requirements longer than a year. Although most spacecraft or satellites have reached their required lifetimes without a lubrication-related failure, the application of liquid lubricants in the space environment presents unique challenges. The state of the art of liquid lubrication in space as well as the problems and their solutions are reviewed.

  6. Korea space program

    NASA Astrophysics Data System (ADS)

    Hong, Jai-Hak

    Though Korea's space activities are just in the infant stage, we are looking forward to joining the advanced countries in the space field. We have three on-going space programs: the KOREASAT Program, a sounding rocket program, and the KITSAT Program. And, we have three more programs that we are in the process of formulating: a small remote sensing satellite program, a data receiving station construction program, and the second generation KOREASAT program. We have several organizations which are involved with space-related activities: KARI, ETRI, SERI, and KAIST. KARI was founded in 1989 in accordance with the Aerospace Industry Development & Promotion Act for the purpose of conducting research on aicraft, satellites and scientific rockets, and supporting national aerospace development projects.

  7. Outlook for space

    NASA Technical Reports Server (NTRS)

    1976-01-01

    Future space activities within the context of national needs were examined, and directions that the United States should take in the civilian use and exploration of space for the time period from 1980 to 2000 were identified. It was decided that the following activities should be pursued: (1) those related to the continuing struggle to improve the quality of life (food production and distribution, new energy sources, etc., (2) those meeting the need for intellectual challenge, for exploration, and for the knowledge by which man can better understand the universe and his relationship to it, (3) those related to research and development in areas applicable to future space systems and missions. A continuing emphasis should be placed on orienting the space program to the physical needs of mankind, to the quest of the mind and spirit, to the vitality of the nation and to the relationship between this nation and other nations of the world.

  8. Space Suit Spins

    NASA Technical Reports Server (NTRS)

    2005-01-01

    Space is a hostile environment where astronauts combat extreme temperatures, dangerous radiation, and a near-breathless vacuum. Life support in these unforgiving circumstances is crucial and complex, and failure is not an option for the devices meant to keep astronauts safe in an environment that presents constant opposition. A space suit must meet stringent requirements for life support. The suit has to be made of durable material to withstand the impact of space debris and protect against radiation. It must provide essential oxygen, pressure, heating, and cooling while retaining mobility and dexterity. It is not a simple article of clothing but rather a complex modern armor that the space explorers must don if they are to continue exploring the heavens

  9. Aboard the Space Shuttle

    NASA Technical Reports Server (NTRS)

    Steinberg, F. S.

    1980-01-01

    Livability aboard the space shuttle orbiter makes it possible for men and women scientists and technicians in reasonably good health to join superbly healthy astronauts as space travelers and workers. Features of the flight deck, the mid-deck living quarters, and the subfloor life support and house-keeping equipment are illustrated as well as the provisions for food preparation, eating, sleeping, exercising, and medical care. Operation of the personal hygiene equipment and of the air revitalization system for maintaining sea level atmosphere in space is described. Capabilities of Spacelab, the purpose and use of the remote manipulator arm, and the design of a permanent space operations center assembled on-orbit by shuttle personnel are also depicted.

  10. Space robotics in Japan

    NASA Astrophysics Data System (ADS)

    Whittaker, William; Lowrie, James W.; McCain, Harry; Bejczy, Antal; Sheridan, Tom; Kanade, Takeo; Allen, Peter

    1994-03-01

    Japan has been one of the most successful countries in the world in the realm of terrestrial robot applications. The panel found that Japan has in place a broad base of robotics research and development, ranging from components to working systems for manufacturing, construction, and human service industries. From this base, Japan looks to the use of robotics in space applications and has funded work in space robotics since the mid-1980's. The Japanese are focusing on a clear image of what they hope to achieve through three objectives for the 1990's: developing long-reach manipulation for tending experiments on Space Station Freedom, capturing satellites using a free-flying manipulator, and surveying part of the moon with a mobile robot. This focus and a sound robotics infrastructure is enabling the young Japanese space program to develop relevant systems for extraterrestrial robotics applications.

  11. Space station power system

    NASA Technical Reports Server (NTRS)

    Baraona, Cosmo R.

    1987-01-01

    The major requirements and guidelines that affect the space station configuration and power system are explained. The evolution of the space station power system from the NASA program development-feasibility phase through the current preliminary design phase is described. Several early station concepts are described and linked to the present concept. Trade study selections of photovoltaic system technologies are described in detail. A summary of present solar dynamic and power management and distribution systems is also given.

  12. European Space Power Conference

    SciTech Connect

    Flood, D.J.

    1991-01-01

    Recent, rapid advances in a variety of solar cell technologies offer the potential for significantly enhancing, or enabling entirely new, mission capabilities. Thin film solar cells are of particular interest in that regard. A review is provided of the status of those thin film cell technologies of interest for space applications, and the issues to be resolved before mission planners can consider them. A short summary is also given of recent developments in concentrator and multijunction space solar cell and array technology.

  13. Biosecurity's unruly spaces.

    PubMed

    Mather, Charles; Marshall, Amy

    2011-01-01

    This paper is about the geopolitics of animal health governance. Through a biosecurity event in South Africa's pig sector we examine changes in the way the governance of disease risk is configuring intra-national spaces. Our case suggests an emerging geopolitics of animal health, one that is defined not by differences between nations but by a more complex patchwork of ‘secure’ and ‘unruly spaces’. PMID:22180920

  14. Autonomous Space Shuttle

    NASA Technical Reports Server (NTRS)

    Siders, Jeffrey A.; Smith, Robert H.

    2004-01-01

    The continued assembly and operation of the International Space Station (ISS) is the cornerstone within NASA's overall Strategic P an. As indicated in NASA's Integrated Space Transportation Plan (ISTP), the International Space Station requires Shuttle to fly through at least the middle of the next decade to complete assembly of the Station, provide crew transport, and to provide heavy lift up and down mass capability. The ISTP reflects a tight coupling among the Station, Shuttle, and OSP programs to support our Nation's space goal . While the Shuttle is a critical component of this ISTP, there is a new emphasis for the need to achieve greater efficiency and safety in transporting crews to and from the Space Station. This need is being addressed through the Orbital Space Plane (OSP) Program. However, the OSP is being designed to "complement" the Shuttle as the primary means for crew transfer, and will not replace all the Shuttle's capabilities. The unique heavy lift capabilities of the Space Shuttle is essential for both ISS, as well as other potential missions extending beyond low Earth orbit. One concept under discussion to better fulfill this role of a heavy lift carrier, is the transformation of the Shuttle to an "un-piloted" autonomous system. This concept would eliminate the loss of crew risk, while providing a substantial increase in payload to orbit capability. Using the guidelines reflected in the NASA ISTP, the autonomous Shuttle a simplified concept of operations can be described as; "a re-supply of cargo to the ISS through the use of an un-piloted Shuttle vehicle from launch through landing". Although this is the primary mission profile, the other major consideration in developing an autonomous Shuttle is maintaining a crew transportation capability to ISS as an assured human access to space capability.

  15. Lithium battery space experiment

    SciTech Connect

    Chmlelewski, A.B.; Surampudi, S.; Bennett, R.; Frank, H.; Mueller, R. [Jet Propulsion Lab., Pasadena, CA (United States)

    1995-12-31

    The In-Space Technology Experiments Program selected the Jet Propulsion Laboratory to conduct a Phase A study of the Lithium Battery Experiment. The experiment will mark the first time a rechargeable lithium battery will be flown in space. The operation of the battery involves lithium deposition and dissolution processes. Micro gravity influences these processes significantly. The experiment will check the rate capability, discharge voltage, capacity and the phenomena affecting cycle life. The paper describes the design and methodology of this experiment.

  16. Introduction to Space Flight

    NSDL National Science Digital Library

    Erickson, Lance

    These online lecture notes introduce students to the basics of space flight. Topics covered include: rocket motors, history of rockets, the scientific method, astronomy basics, the solar system, the universe, space flight missions, spacecraft, remote sensing, astronauts, and future spaceflight missions. This website also provides useful links and exercises intended for students taking this course. These exercises can provide teachers with ideas for their own classes.

  17. Man in space

    NASA Technical Reports Server (NTRS)

    West, J. B.

    1986-01-01

    The Challenger disaster focused attention on the hazards as well as the possibilities of man in space. The physiological effects of prolonged weightlessness include important changes in vestibular, bone, muscle, cardiovascular, blood, renal, and pulmonary function. Much has been learned from US and Soviet experiments, but large areas of ignorance remain. Exceptional opportunities for physiological research are provided by Spacelab, a pressurized laboratory planned as a payload of the Space Shuttle.

  18. Space trophy nominations sought

    NASA Astrophysics Data System (ADS)

    Showstack, Randy

    2011-10-01

    The Rotary National Award for Space Achievement (RNASA) Foundation is soliciting nominations for its 2012 trophy. The trophy recognizes an outstanding American who has made major contributions to the U.S. space program. Previous awardees include astronaut Neil Armstrong and President George H. W. Bush. Nominations are due by 6 November 2011. For more information, see http://www.rnasa.org/trophy.html or contact chairman@rnasa.org.

  19. Space Stations: Measure Up!

    NSDL National Science Digital Library

    Dr. Diane Byerly

    2006-01-01

    In this activity, learners work in pairs to measure each other's ankles with lengths of string. Learners make measurements both before and after lying on their backs with their feet in the air for 1 minute. This simulates the microgravity of space, where everything--including body fluids--floats! This activity station is part of a sequence of stations that can be set up to help learners explore how space affects the human body and why.

  20. Space Mechanisms Technology Workshop

    NASA Technical Reports Server (NTRS)

    Oswald, Fred B. (Editor)

    2002-01-01

    The Mechanical Components Branch at NASA Glenn Research Center hosted a workshop on Tuesday, May 14, 2002, to discuss space mechanisms technology. The theme for this workshop was 'Working in the Cold,' a focus on space mechanisms that must operate at low temperatures. We define 'cold' as below -60C (210 K), such as would be found near the equator of Mars. However, we are also concerned with much colder temperatures such as in permanently dark craters of the Moon (about 40 K).

  1. Space Tethers: Design Criteria

    NASA Technical Reports Server (NTRS)

    Tomlin, D. D.; Faile, G. C.; Hayashida, K. B.; Frost, C. L.; Wagner, C. Y.; Mitchell, M. L.; Vaughn, J. A.; Galuska, M. J.

    1997-01-01

    This document is prepared to provide a systematic process for the selection of tethers for space applications. Criteria arc provided for determining the strength requirement for tether missions and for mission success from tether severing due to micrometeoroids and orbital debris particle impacts. Background information of materials for use in space tethers is provided, including electricity-conducting tethers. Dynamic considerations for tether selection is also provided. Safety, quality, and reliability considerations are provided for a tether project.

  2. The NORAD space network

    Microsoft Academic Search

    G. T. Devere; N. L. Johnson

    1985-01-01

    The crew, capabilities and operations of the NORAD Space Sensor Network (SSN) are described. The 24 hr\\/day, 7 day\\/week operation tracks 5000 orbiting man-made objects, including both satellites and debris. The data serves for identifying new objects, predicting reentry paths, planning orbits which minimize collision risks, and tracking the orbits of objects in space. Data are gathered from a worldwide

  3. Space Station lubrication considerations

    NASA Technical Reports Server (NTRS)

    Leger, Lubert J.; Dufrane, Keith

    1987-01-01

    Future activities in space will require the use of large structures and high power availability in order to fully exploit opportunities in Earth and stellar observations, space manufacturing and the development of optimum space transportation vehicles. Although these large systems will have increased capabilities, the associated development costs will be high, and will dictate long life with minimum maintenance. The Space Station provides a concrete example of such a system; it is approximately one hundred meters in major dimensions and has a life requirement of thirty years. Numerous mechanical components will be associated with these systems, a portion of which will be exposed to the space environment. If the long life and low maintenance goals are to be satisfied, lubricants and lubrication concepts will have to be carefully selected. Current lubrication practices are reviewed with the intent of determining acceptability for the long life requirements. The effects of exposure of lubricants and lubricant binders to the space environment are generally discussed. Potential interaction of MoS2 with atomic oxygen, a component of the low Earth orbit environment, appears to be significant.

  4. Distributed Space Solar Power

    NASA Technical Reports Server (NTRS)

    Fork, Richard L.

    2001-01-01

    The objective was to assess the feasibility of safely collecting solar power at geostationary orbit and delivering it to earth. A strategy which could harness a small fraction of the millions of gigawatts of sunlight passing near earth could adequately supply the power needs of earth and those of space exploration far into the future. Light collected and enhanced both spatially and temporally in space and beamed to earth provides probably the only practical means of safe and efficient delivery of this space solar power to earth. In particular, we analyzed the feasibility of delivering power to sites on earth at a comparable intensity, after conversion to a usable form, to existing power needs. Two major obstacles in the delivery of space solar power to earth are safety and the development of a source suitable for space. We focused our approach on: (1) identifying system requirements and designing a strategy satisfying current eye and skin safety requirements; and (2) identifying a concept for a potential space-based source for producing the enhanced light.

  5. National Aeronautics and Space Administration International Space StationInternational Space Station

    E-print Network

    Christian, Eric

    National Aeronautics and Space Administration International Space StationInternational Space.nasa.gov #12;Current Stage National Aeronautics and Space Administration Rod Jones ISS Payloads Office 2 #12, Japan, and Russia National Aeronautics and Space Administration 3 US, Europe, Japan, and Russia #12

  6. Translational Research in Space Exploration

    NASA Technical Reports Server (NTRS)

    Iyengar, M. Sriram; Johnson-Throop, Kathy A.; Bernstam, Elmer; Meric-Bernstam, Funda

    2007-01-01

    This viewgraph presentation reviews NASA's role in medical translational research, and the importance in research for space exploration. The application of medical research for space exploration translates to health care in space medicine, and on earth.

  7. National Space Development Agency, Japan

    NASA Astrophysics Data System (ADS)

    Murdin, P.

    2000-11-01

    The National Space Development Agency (NASDA) was established by the Japanese government in 1969 to act as the nucleus for the development of space exploration and to promote the peaceful use of space and its practical applications....

  8. International Space Exploration Coordination Group

    E-print Network

    International Space Exploration Coordination Group The Global Exploration Roadmap September 2011, and stimulating technical and commercial innovation. As more nations undertake space exploration activities agencies participating in the International Space Exploration Coordination Group (ISECG) are developing

  9. Space, Energy, Pollution--Which?

    ERIC Educational Resources Information Center

    O'Leary, Brian

    1973-01-01

    Criticizes the rapidly escalating expenditures in space exploration and suggests the establishment of a moderate unmanned space program in place of the space shuttle in an effort to allocate enough budget for energy research and pollution control. (CC)

  10. International Space Exploration Coordination Group

    E-print Network

    International Space Exploration Coordination Group The Global Exploration Roadmap September 2011 participating in the International Space Exploration Coordination Group (ISECG) are developing the Global. Agencies agree that human space exploration will be most successful as an international endeavor because

  11. Enabling Space Science and Exploration

    NASA Technical Reports Server (NTRS)

    Weber, William J.

    2006-01-01

    This viewgraph presentation on enabling space science and exploration covers the following topics: 1) Today s Deep Space Network; 2) Next Generation Deep Space Network; 3) Needed technologies; 4) Mission IT and networking; and 5) Multi-mission operations.

  12. Benefits Stemming from Space Exploration

    E-print Network

    Waliser, Duane E.

    Benefits Stemming from Space Exploration September 2013 International Space Exploration Coordination Group #12; This page is intentionally left blank #12;ISECG ­ Benefits Stemming from Space Exploration Table of Content Executive Summary

  13. Birth of space plant growing

    NASA Technical Reports Server (NTRS)

    Mashinskiy, A.; Nechitaylo, G.

    1983-01-01

    The attempts, and successes, to grow plants in space, and get them to fully develop, bloom and produce seeds using orchids are presented. The psychological advantages of the presence of plants onboard space vehicles and space stations is indicated.

  14. National Aeronautics and Space Administration

    E-print Network

    Waliser, Duane E.

    National Aeronautics and Space Administration Jet Propulsion Laboratory California Institute-kilometer data set) #12;National Aeronautics and Space Administration Jet Propulsion Laboratory California- cialist; and (bottom row, left to right) Mamoru Mohri, Mis- sion Specialist, National Space Development

  15. National Aeronautics and Space Administration

    E-print Network

    National Aeronautics and Space Administration Jet Propulsion Laboratory California Institute and TES Science Team, JPL/Caltech #12;National Aeronautics and Space Administration Jet Propulsion of ozone #12;National Aeronautics and Space Administration Jet Propulsion Laboratory California Institute

  16. National Aeronautics and Space Administration

    E-print Network

    Bordoni, Simona

    National Aeronautics and Space Administration Jet Propulsion Laboratory California Institute surface #12;National Aeronautics and Space Administration Jet Propulsion Laboratory California Institute;National Aeronautics and Space Administration Jet Propulsion Laboratory California Institute of Technology

  17. National Aeronautics and Space Administration

    E-print Network

    Christian, Eric

    National Aeronautics and Space Administration Jet Propulsion Laboratory California Institute (January `10) · Transition to Phase C (March `10) #12;National Aeronautics and Space Administration Jet Aeronautics and Space Administration Soil Moisture Active and Passive (SMAP) Mission Decadal Survey Workshop

  18. National Aeronautics and Space Administration

    E-print Network

    Waliser, Duane E.

    National Aeronautics and Space Administration Customer Service Plan October 20, 2011 The National Aeronautics and Space Administration (NASA) has a long tradition of enabling of the agency's human space flight programs, science and aeronautic missions, agency news

  19. National Aeronautics and Space Administration

    E-print Network

    National Aeronautics and Space Administration Jet Propulsion Laboratory California Institute The vertical distribution of ozone #12;National Aeronautics and Space Administration Jet Propulsion Laboratory;National Aeronautics and Space Administration Jet Propulsion Laboratory California Institute of Technology

  20. NATIONAL AERONAUTICS AND SPACE ADMINISTRATION

    E-print Network

    Christian, Eric

    NATIONAL AERONAUTICS AND SPACE ADMINISTRATION 1 NASA Earth Science Data Systems Software Reuse #12;NATIONAL AERONAUTICS AND SPACE ADMINISTRATION ESDS Reuse Working Group 2 Award Background: http://www.esdswg.com/softwarereuse/Resources/awards/ #12;NATIONAL AERONAUTICS AND SPACE ADMINISTRATION

  1. National Aeronautics and Space Administration

    E-print Network

    Waliser, Duane E.

    National Aeronautics and Space Administration Jet Propulsion Laboratory California Institute September 18, 2012 #12;National Aeronautics and Space Administration Jet Propulsion Laboratory California Science Human exploration Aeronautics 28% 45% 3% #12;National Aeronautics and Space Administration Jet

  2. NATIONAL AERONAUTICS AND SPACE ADMINISTRATION

    E-print Network

    NATIONAL AERONAUTICS AND SPACE ADMINISTRATION NASA's Earth Science Data Systems WG Standards;NATIONAL AERONAUTICS AND SPACE ADMINISTRATION 17 August, 2004 ESDS Standards Process 1 Conclusions are seeking additional community leadership! #12;NATIONAL AERONAUTICS AND SPACE ADMINISTRATION 17 August, 2004

  3. NATIONAL AERONAUTICS AND SPACE ADMINISTRATION

    E-print Network

    NATIONAL AERONAUTICS AND SPACE ADMINISTRATION Earth Science Data Systems Working Group Standards-identified practices. #12;NATIONAL AERONAUTICS AND SPACE ADMINISTRATION The Standards Process Group (SPG) · History #12;NATIONAL AERONAUTICS AND SPACE ADMINISTRATION Insights (why the SPG?) · Interoperability does

  4. National Aeronautics and Space Administration

    E-print Network

    National Aeronautics and Space Administration Jet Propulsion Laboratory California Institute. Government sponsorship acknowledged. #12;National Aeronautics and Space Administration Jet Propulsion GlobalTESozone 2 #12;National Aeronautics and Space Administration Jet Propulsion Laboratory California

  5. Space Electronic Test Engineering

    NASA Technical Reports Server (NTRS)

    Chambers, Rodney D.

    2004-01-01

    The Space Power and Propulsion Test Engineering Branch at NASA Glenn Research center has the important duty of controlling electronic test engineering services. These services include test planning and early assessment of Space projects, management and/or technical support required to safely and effectively prepare the article and facility for testing, operation of test facilities, and validation/delivery of data to customer. The Space Electronic Test Engineering Branch is assigned electronic test engineering responsibility for the GRC Space Simulation, Microgravity, Cryogenic, and Combustion Test Facilities. While working with the Space Power and Propulsion Test Engineering Branch I am working on several different assignments. My primary assignment deals with an electrical hardware unit known as Sunny Boy. Sunny Boy is a DC load Bank that is designed for solar arrays in which it is used to convert DC power form the solar arrays into AC power at 60 hertz to pump back into the electricity grid. However, there are some researchers who decided that they would like to use the Sunny Boy unit in a space simulation as a DC load bank for a space shuttle or even the International Space Station hardware. In order to do so I must create a communication link between a computer and the Sunny Boy unit so that I can preset a few of the limits (such power, set & constant voltage levels) that Sunny Boy will need to operate using the applied DC load. Apart from this assignment I am also working on a hi-tech circuit that I need to have built at a researcher s request. This is a high voltage analog to digital circuit that will be used to record data from space ion propulsion rocket booster tests. The problem that makes building this circuit so difficult is that it contains high voltage we must find a way to lower the voltage signal before the data is transferred into the computer to be read. The solution to this problem was to transport the signal using infrared light which will lower the voltage signal down low enough so that it is harmless to a computer. Along with my involvement in the Space Power and Propulsion Test Engineering Branch, I am obligated to assist all other members of the branch in their work. This will help me to strengthen and extend my knowledge of Electrical Engineering.

  6. DOD Space Test Program (STP)

    NASA Technical Reports Server (NTRS)

    Smith, Llwyn

    1995-01-01

    This paper describes the Space Test Program (STP) which provides access to space for the DOD-wide space research and development (R&D) community. STP matches a ranked list of sanctioned experiments with available budgets and searches for the most cost effective mechanisms to get the experiments into space. The program has successfully flown over 350 experiments, using dedicated freeflyer spacecraft, secondary space on the Space Shuttle, and various host satellites.

  7. HUBBLE SPACE TELESCOPE SPECTRAL OBSERVATIONS NEAR THE He II Ly{alpha} BREAK: IMPLICATIONS FOR He II REIONIZATION

    SciTech Connect

    Syphers, David [CASA, Department of Astrophysical and Planetary Sciences, University of Colorado, Boulder, CO 80309 (United States); Anderson, Scott F.; Haggard, Daryl [Astronomy Department, University of Washington, Seattle, WA 98195 (United States); Zheng Wei [Department of Physics and Astronomy, Johns Hopkins University, Baltimore, MD 21218 (United States); Meiksin, Avery [Scottish Universities Physics Alliance (SUPA), Institute for Astronomy, University of Edinburgh, Royal Observatory, Edinburgh EH9 3HJ (United Kingdom); Schneider, Donald P. [Department of Physics and Astronomy, Pennsylvania State University, 525 Davey Lab, University Park, PA 16802 (United States); York, Donald G., E-mail: David.Syphers@colorado.edu, E-mail: anderson@astro.washington.edu, E-mail: zheng@pha.jhu.edu [Department of Astronomy and Astrophysics, University of Chicago, 5640 South Ellis Avenue, Chicago, IL 60637 (United States)

    2011-01-10

    Quasars that allow the study of intergalactic medium (IGM) He II are very rare, since they must be at high redshift along sightlines free of substantial hydrogen absorption, but recent work has dramatically expanded the number of such quasars known. We analyze two dozen higher-redshift (z = 3.1-3.9) low-resolution He II quasar spectra from the Hubble Space Telescope and find that their He II Gunn-Peterson troughs suggest exclusion of very early and very late reionization models, favoring a reionization redshift of z {approx} 3. Although the data quality is not sufficient to reveal details such as the expected redshift evolution of helium opacity, we obtain the first ensemble measure of helium opacity at high redshift averaged over many sightlines: {tau} = 4.90 at z {approx} 3.3. We also find that it would be very difficult to observe the IGM red wing of absorption from the beginning of He II reionization, but depending on the redshift of reionization and the size of ionization zones, it might be possible to do so in some objects with the current generation of UV spectrographs.

  8. Capacity building in space law and space policy

    NASA Astrophysics Data System (ADS)

    Jakhu, Ram

    2009-11-01

    A high level of expertise in space policy and law is required to initiate and keep pace with the expansion of space activities, including those undertaken by the private space industry. Space activities generally refer to those undertakings that are carried out with the use of several technologies for the exploration and utilization of outer space often for scientific, military, economic and social proposes within international and national policy and regulatory frameworks. Space policies and legal regimes determine the scope, nature, pace, possibility and development of space undertakings. Therefore, appropriate space policies and regulatory regimes, both at the international and national levels, are indispensable for the initiation, operation and enhancement of space activities. There are various regulatory models and approaches for regulating space activities, and for building capacity in space law and space policy. It is imperative to have the appropriate human resources and capabilities in the development and implementation of space policies and space legal regimes. This crucial requirement has been well recognized in the more advanced space-faring nations, but not to the same level in other space-faring or space-aspiring nations.

  9. Women in Space

    NASA Astrophysics Data System (ADS)

    Mukai, Chiaki

    Since 1963 women have successfully flown and worked in space so much so that having a female aboard the shuttle, on Soyuz or on the International Space Station is considered commonplace. We do know that women have historically been virturally equal in capabilities and performance with their male counterparts. For example, there have been superb shuttle pilots, shuttle commanders, EVA participants as well as mission specialists and payload specialists. Thus, gender is not an issue within the ranks, rather a simple fact. In addition, there is a positive psychological factor that has been noted in that a mixed crew seems to have better intercommunications dynamics. JAXA has conducted the experiments on 7 subjects on bone mineral density in short duration of space flight and noticed a slight decrease in that density in both male and female. Lean body mass was also examined and found to be reduced by 3.0 % on average. There was no significant difference between male and female subjects in short duration of space flight. Unfortunately, only 1 of the 7 subjects was a woman. In fact, only 48 women have flown in total, some more than once, and science is still discovering the effects of the space experience. This is due to the limited exposure on orbit and in microgravity and the limited number of potential subjects. Time in space is beginning to increase with the continued progress of the ISS, thereby creating a demand for more knowledge on what effects long term exposure will have on the female of the species. The presentation will address these and other concerns involved with women in space from the perspective of a female scientist and an astronaut.

  10. Mammalian development in space

    NASA Technical Reports Server (NTRS)

    Ronca, April E.

    2003-01-01

    Life on Earth, and thus the reproductive and ontogenetic processes of all extant species and their ancestors, evolved under the constant influence of the Earth's l g gravitational field. These considerations raise important questions about the ability of mammals to reproduce and develop in space. In this chapter, I review the current state of our knowledge of spaceflight effects on developing mammals. Recent studies are revealing the first insights into how the space environment affects critical phases of mammalian reproduction and development, viz., those events surrounding fertilization, embryogenesis, pregnancy, birth, postnatal maturation and parental care. This review emphasizes fetal and early postnatal life, the developmental epochs for which the greatest amounts of mammalian spaceflight data have been amassed. The maternal-offspring system, the coordinated aggregate of mother and young comprising mammalian development, is of primary importance during these early, formative developmental phases. The existing research supports the view that biologically meaningful interactions between mothers and offspring are changed in the weightlessness of space. These changes may, in turn, cloud interpretations of spaceflight effects on developing offspring. Whereas studies of mid-pregnant rats in space have been extraordinarily successful, studies of young rat litters launched at 9 days of postnatal age or earlier, have been encumbered with problems related to the design of in-flight caging and compromised maternal-offspring interactions. Possibilities for mammalian birth in space, an event that has not yet transpired, are considered. In the aggregate, the results indicate a strong need for new studies of mammalian reproduction and development in space. Habitat development and systematic ground-based testing are important prerequisites to future research with young postnatal rodents in space. Together, the findings support the view that the environment within which young mammals develop, comprised of its mother and siblings, is of paramount importance in interpreting spaceflight effects.

  11. National Aeronautics and Space Administration

    E-print Network

    Frey, Pascal

    National Aeronautics and Space Administration Langley Research Center Hampton, Virginia 23681 Applications in Science and Engineering NASA Langley Research Center Hampton, VA Operated by Universities Space

  12. Space station contamination modeling

    NASA Technical Reports Server (NTRS)

    Gordon, T. D.

    1989-01-01

    Current plans for the operation of Space Station Freedom allow the orbit to decay to approximately an altitude of 200 km before reboosting to approximately 450 km. The Space Station will encounter dramatically increasing ambient and induced environmental effects as the orbit decays. Unfortunately, Shuttle docking, which has been of concern as a high contamination period, will likely occur during the time when the station is in the lowest orbit. The combination of ambient and induced environments along with the presence of the docked Shuttle could cause very severe contamination conditions at the lower orbital altitudes prior to Space Station reboost. The purpose here is to determine the effects on the induced external environment of Space Station Freedom with regard to the proposed changes in altitude. The change in the induced environment will be manifest in several parameters. The ambient density buildup in front of ram facing surfaces will change. The source of such contaminants can be outgassing/offgassing surfaces, leakage from the pressurized modules or experiments, purposeful venting, and thruster firings. The third induced environment parameter with altitude dependence is the glow. In order to determine the altitude dependence of the induced environment parameters, researchers used the integrated Spacecraft Environment Model (ISEM) which was developed for Marshall Space Flight Center. The analysis required numerous ISEM runs. The assumptions and limitations for the ISEM runs are described.

  13. Antarctic Space Analog Program

    NASA Technical Reports Server (NTRS)

    Palinkas, Lawrence A; Gunderson, E. K. Eric; Johnson, Jeffrey C.; Holland, Albert W.

    1998-01-01

    The primary aim of this project was to examine group dynamics and individual performance in extreme, isolated environments and identify human factors requirements for long-duration space missions using data collected in an analog environment. Specifically, we wished to determine: 1) the characteristics of social relations in small groups of individuals living and working together in extreme, isolated environments, and 2) the environmental, social and psychological determinants of performance effectiveness in such groups. These two issues were examined in six interrelated studies using data collected in small, isolated research stations in Antarctica from 1963 to the present. Results from these six studies indicated that behavior and performance on long-duration space flights is likely to be seasonal or cyclical, situational, social, and salutogenic in nature. The project responded to two NASA program emphases for FY 1997 as described in the NRA: 1) the primary emphasis of the Behavior and Performance Program on determining long-term individual and group performance responses to space, identifying critical factors affecting those responses and understanding underlying mechanisms involved in behavior and performance, and developing and using ground-based models and analogs for studying space-related behavior and performance; and 2) the emphasis of the Data Analysis Program on extended data analysis. Results from the study were used to develop recommendations for the design and development of pre-flight crew training and in-flight psychological countermeasures for long-duration manned space missions.

  14. Reusable space tug concepts

    SciTech Connect

    Earley, S.M. [Martin Marietta Astronautics, P.O. Box 179 (M/S: S-5060), Denver, Colorado 80201 (United States)

    1995-01-20

    Initial findings indicate that a space tug transportation system could potentially support up to 30 to 40 missions a year with cost savings being mission dependent. This study identified two large expensable launch system class government missions, projected to fly approximately four times a year, which could yield a total annual savings of approximately $500 million. With the nominal flight rate of four flights annually, a minimum savings of $130 million per flight is projected. Based on this cost savings, recovery of the non-recurring costs of design, development, test and evaluation of the space tug should occur in five to ten years. For the remaining missions considered, the payload delivery capabilities of the space tug met or exceeded those of existing orbital transfer systems, the payload delivery capabilities of the space tug met or exceeded those of existing orbital transfer systems, but did not produce sufficient economic benefit to justify its use. However, even for these ``economically insupportable`` missions, a space tug might provide the existing launch systems additional flexibility and/or payload capability, enhancing the potential of supporting future commercial, civil, and defense missions. {copyright} {ital 1995} {ital American} {ital Institute} {ital of} {ital Physics}

  15. Hydrogen masers for space

    NASA Technical Reports Server (NTRS)

    Vessot, R. F. C.; Mattison, E. M.; Nystrom, G. U.; Coyle, L. M.; Decher, R.; Feltham, S. J.; Busca, G.; Starker, S.; Leschiutta, S.

    1992-01-01

    A program for the design and testing of atomic hydrogen (H) masers for general use in space and methods for high precision space to Earth time and frequency comparisons are described. Because of the similarity of the space masers' basic components to those of existing terrestrial masers, their frequency stability is expected to reach well below 1 part in 10(exp 15) for intervals between 1000 and 100,000 sec. A NASA funded development program at the Smithsonian Astrophysical Observatory (SAO), currently in a conceptual design phase, is specifically directed toward producing an H laser for space and testing it for 6 months in the ESA Eureca spacecraft. The maser design will have the capability to cope with stringent dynamic load test levels and will have sufficient lifetime for long term continuous operation in future deep space missions such as a close approach solar probe. The time comparison system for the Eureca test mission will use high precision (less than 50 ps) pulsed laser time transfer between the spacecraft and H maser equipped laser ranging Earth stations. European studies of the proposed inclusion of a second H maser for direct onboard frequency comparisons and of a modified PRARE (Precise Range and Range rate Equipment) microwave system (in addition to the laser system) for worldwide time synchronization are also discussed.

  16. Reusable space tug concepts

    NASA Astrophysics Data System (ADS)

    Earley, Sidney M.

    1995-01-01

    Initial findings indicate that a space tug transportation system could potentially support up to 30 to 40 missions a year with cost savings being mission dependent. This study identified two large expensable launch system class government missions, projected to fly approximately four times a year, which could yield a total annual savings of approximately 500 million. With the nominal flight rate of four flights annually, a minimum savings of 130 million per flight is projected. Based on this cost savings, recovery of the non-recurring costs of design, development, test and evaluation of the space tug should occur in five to ten years. For the remaining missions considered, the payload delivery capabilities of the space tug met or exceeded those of existing orbital transfer systems, the payload delivery capabilities of the space tug met or exceeded those of existing orbital transfer systems, but did not produce sufficient economic benefit to justify its use. However, even for these ``economically insupportable'' missions, a space tug might provide the existing launch systems additional flexibility and/or payload capability, enhancing the potential of supporting future commercial, civil, and defense missions.

  17. MEMS in Space Systems

    NASA Technical Reports Server (NTRS)

    Lyke, J. C.; Michalicek, M. A.; Singaraju, B. K.

    1995-01-01

    Micro-electro-mechanical systems (MEMS) provide an emerging technology that has the potential for revolutionizing the way space systems are designed, assembled, and tested. The high launch costs of current space systems are a major determining factor in the amount of functionality that can be integrated in a typical space system. MEMS devices have the ability to increase the functionality of selected satellite subsystems while simultaneously decreasing spacecraft weight. The Air Force Phillips Laboratory (PL) is supporting the development of a variety of MEMS related technologies as one of several methods to reduce the weight of space systems and increase their performance. MEMS research is a natural extension of PL research objectives in micro-electronics and advanced packaging. Examples of applications that are under research include on-chip micro-coolers, micro-gyroscopes, vibration sensors, and three-dimensional packaging technologies to integrate electronics with MEMS devices. The first on-orbit space flight demonstration of these and other technologies is scheduled for next year.

  18. Space Resources Utilization Roundtable

    NASA Astrophysics Data System (ADS)

    1999-01-01

    This volume contains abstracts on various topics. These topics include; Economics of Lunar Mineral Exploration; Lunar Solar Power System and Lunar Development; Space Resource Roundtable Rationale; Successfully Mining Asteroids and Comets; Lunar Polar Ice: Method for Mining the New Resource for Exploration; Acoustic Shaping: Enabling Technology for a Space-based Economy; Return to the Moon: A New Strategic Evaluation; Spacewatch Discovery and Study of Accessible Asteroids; Role of Mining in Space Development; A Commercial/Lunar Resources Exploration Concept; Radar Reconnaissance of Near-Earth Asteroids; Solar Energy Conversion Using In Situ Lunar Soil; The Application of Thermal Plasmas to Ore Reduction for In Situ Resource Utilization; Prospecting Near-Earth Asteroids from the Ground; Some Implications of Space Tourism for Extraterrestrial Resources; An Overview of NASA's Current In Situ Consumable Production (ISCP) Development Activities and Goals; Prospectives on Lunar Helium-3; Self-Propagating High-Temperature Synthesis for In Situ Materials Processing; Subsurface Exploration from Lander and Rover Platforms with Seismic Surface Waves; Space Weathering and the Formation of Lunar Soil: The Moon as the Model for all Airless Bodies in the Solar System; and Acoustic Shaping in Microgravity: Technology Issues.

  19. Supporting Commercial Space Development Supporting Commercial Space Development

    E-print Network

    Supporting Commercial Space Development Part 1 Supporting Commercial Space Development Part 1 Commercial Space Development Part 1: Support Alternatives versus Investor Risk Perceptions & Tolerances Administration or the United States Government. 1 of 228 #12;Supporting Commercial Space Development Part 1 "When

  20. Properly injective spaces and function spaces Martin Hotzel Escardo

    E-print Network

    Escardó, Martín

    Properly injective spaces and function spaces Mart´in H¨otzel Escard´o To appear in Topology and Its Applications Version of Monday 22 nd September 1997 Abstract Given an injective space D (a embedding. We show that the extension map is Scott continuous iff D is the trivial one-point space or j