NASA Technical Reports Server (NTRS)
The NTRS is a valuable resource for students, educators, researchers, and the public for access to NASA's current and historical technical literature since it was first released in 1994. NTRS provides access to approximately 500K aerospace related citations, 90K full-text online documents, and 111K images and videos. NTRS numbers continues to grow over time as new scientific and technical information (STI) is created or funded by NASA. The type of information found in NTRS include: conference papers, images, journal articles, photos, meeting papers, movies, patents, research reports, and technical videos.
Plasma in Saturn's Nightside Magnetosphere and the Implications for Global Circulation - McAndrews, H.J.; Sittler, E. C.; Coates, A.J.; Henderson, M.G.; Arridge, C.S.; Thomsen, M.F.; Tokar, R.L.; Jackman, C.M.; Wilson, R.J.; Dougherty, M.K.; Khurana, K.K.
We present a bulk ion flow map from the nightside, equatorial region of Saturn's magnetosphere derived from the Cassini CAPS ion mass spectrometer data. The map clearly demonstrates the dominance of corotation flow over radial flow and suggests that the flux tubes sampled are still closed and attached to the planet up to distances of 50RS. The plasma characteristics in the near-midnight region are described and indicate a transition between the region of the magnetosphere containing plasma on closed drift paths and that containing flux tubes which may not complete a full rotation around the planet. Data from the electron...
An Accreting White Dwarf near the Chandrasekhar Limit in the Andromeda Galaxy - Wolf, William M.; Kong, Albert K. H.; Kulkarni, Shrinivas R.; Bildsten, Lars; Perley, Daniel A.; Tang, Sumin; Surace, Jason; Prince, Thomas A.; Laher, Russ R.; Cao, Yi; De Cia, Annalisa; Li, K. L.; Nugent, Peter E.; Kasliwal, Mansi M.; Cenko, S. Bradley; Masci, Frank
The iPTF (Intermediate Palomar Transient Factory) detection of the most recent outburst of the recurrent nova system RX J0045.4+4154 in the Andromeda Galaxy has enabled the unprecedented study of a massive (mass is greater than 1.3 solar masses) accreting white dwarf (WD). We detected this nova as part of the near daily iPTF monitoring of M31 to a depth of R (red band-pass filter) approximately equal to magnitude 21 and triggered optical photometry, spectroscopy and soft X-ray monitoring of the outburst. Peaking at an absolute magnitude of MR (red, mid-infrared band-pass filter) equals magnitude 6.6, and with a decay time...
A Chandra-Swift View of Point Sources in Hickson Compact Groups: High AGN Fraction but a Dearth of Strong AGNs - Hornschemeier, A. E.; Desjardins, T. D.; Eracleous, M.; Gronwall, C.; Charlton, J. C.; Fedotov, K.; Tzanavaris, P.; Gallagher, S. C.; Brandt, W. N.
We present Chandra X-ray point source catalogs for 9 Hickson Compact Groups (HCGs, 37 galaxies) at distances of 34-89 Mpc. We perform detailed X-ray point source detection and photometry and interpret the point source population by means of simulated hardness ratios. We thus estimate X-ray luminosities (L(sub x)) for all sources, most of which are too weak for reliable spectral fitting. For all sources, we provide catalogs with counts, count rates, power-law indices (gamma), hardness ratios, and L(sub X), in the full (0.5-8.0 keV), soft (0.5-2.0 keV), and hard (2.0-8.0 keV) bands. We use optical emission-line ratios from the literature...
Fermi: The Gamma-Ray Large Area Space Telescope Mission Status - McEnery, Julie E
Following its launch in June 2008, high-energy gamma-ray observations by the Fermi Gamma-ray Space Telescope have unveiled over 1000 new sources and opened an important and previously unexplored window on a wide variety of phenomena. These have included the discovery of a population of pulsars pulsing only in gamma rays; the detection of photons up to 10s of gigaelectronvolts from gamma-ray bursts, enhancing our understanding of the astrophysics of these powerful explosions; the detection of hundreds of active galaxies; a measurement of the high energy cosmic-ray electron spectrum which may imply the presence of nearby astrophysical particle accelerators; the determination...
SN 2010ay Is a Luminous and Broad-Lined Type Ic Supernova Within a Low-Metallicity Host Galaxy - Foley, R. J.; Grav, T.; Smartt, S.; Golenetskii, S.; Terada, Y.; Heasley, J. N.; Botticella, M. T.; Mazets, E.; Cline, T.; Sanders, N. E.; Barthelmy, S. D.; Boynton, W.; Soderberg, A. M.; Hurley, K.; Valenti, S.; Chomiuk, L.; Gehrels, N.; Levesque, E. M.; Chambers, K. C.; Briggs, M. S.; Berger, E.; Chornock, R.; Narayan, G.; Connaughton, V.; von Kienlin, A.
We report on our serendipitous pre-discovery detection and follow-up observations of the broad-lined Type Ic supernova (SN Ic) 2010ay at z = 0.067 imaged by the Pan-STARRS1 3pi survey just approximately 4 days after explosion. The supernova (SN) had a peak luminosity, MR approx. -20.2 mag, significantly more luminous than known GRB-SNe and one of the most luminous SNe Ib/c ever discovered. The absorption velocity of SN 2010ay is v Si (is) approx. 1910(exp 3) km s1 at approximately 40 days after explosion, 2-5 times higher than other broad-lined SNe and similar to the GRB-SN 2010bh at comparable epochs. Moreover,...
Dynamics of the Transition Corona - Golub, Leon; DeLuca, Edward E.; Masson, Sophie; Reeves, Katharine K.; McCauley, Patrick
Magnetic reconnection between the open and closed magnetic fields in the corona is believed to play a crucial role in the corona/heliosphere coupling. At large scale, the exchange of open/closed connectivity is expected to occur in pseudo-streamer (PS) structures. However, there is neither clear observational evidence of how such coupling occurs in PSs, nor evidence for how the magnetic reconnection evolves. Using a newly developed technique, we enhance the off-limb magnetic fine structures observed with the Atmospheric Imaging Assembly and identify a PS-like feature located close to the northern coronal hole. We first identify that the magnetic topology associated with...
Time-Series Analysis of Supergranule Characterstics at Solar Minimum - Pesnell, W. Dean; Williams, Peter E.
Sixty days of Doppler images from the Solar and Heliospheric Observatory (SOHO) / Michelson Doppler Imager (MDI) investigation during the 1996 and 2008 solar minima have been analyzed to show that certain supergranule characteristics (size, size range, and horizontal velocity) exhibit fluctuations of three to five days. Cross-correlating parameters showed a good, positive correlation between supergranulation size and size range, and a moderate, negative correlation between size range and velocity. The size and velocity do exhibit a moderate, negative correlation, but with a small time lag (less than 12 hours). Supergranule sizes during five days of co-temporal data from MDI...
Do Solar Coronal Holes Affect the Properties of Solar Energetic Particle Events? - Kahler, S. W.; Arge, C. N.; Gopalswamy, N.; Akiyama, S.
The intensities and timescales of gradual solar energetic particle (SEP) events at 1 AU may depend not only on the characteristics of shocks driven by coronal mass ejections (CMEs), but also on large-scale coronal and interplanetary structures. It has long been suspected that the presence of coronal holes (CHs) near the CMEs or near the 1-AU magnetic footpoints may be an important factor in SEP events. We used a group of 41 E (is) approx. 20 MeV SEP events with origins near the solar central meridian to search for such effects. First we investigated whether the presence of a CH...
Transport Powder and Liquid Samples by Surface Acoustic Waves - Sherrit, Stewart; Bar-Cohen, Yoseph; Bao, Xiaoqi; Louyeh, Sahar; Badescu, Mircea
Sample transport is an important requirement for In-situ analysis of samples in NASA planetary exploration missions. Tests have shown that powders or liquid drops on a surface can be transported by surface acoustic waves (SAW) that are generated on the surface using interdigital transducers. The phenomena were investigated experimentally and to generate SAWs interdigital electrodes were deposited on wafers of 128 deg rotated Y-cut LiNbO?. Transporting capability of the SAW device was tested using particles of various sizes and drops of various viscosities liquids. Because of different interaction mechanisms with the SAWs, the powders and the liquid drops were observed...