226,607 research outputs found
A 2 h periodic variation in the low-mass X-ray binary Ser X-1
No full textSpectroscopy of the low-mass X-ray binary Ser X-1 using the Gran Telescopio Canarias have revealed a ?2 h periodic variability that is present in the three strongest emission lines. We tentatively interpret this variability as due to orbital motion, making it the first indication of the orbital period of Ser X-1. Together with the fact that the emission lines are remarkably narrow, but still resolved, we show that a main-sequence K dwarf together with a canonical 1.4 M? neutron star gives a good description of the system. In this scenario, the most likely place for the emission lines to arise is the accretion disc, instead of a localized region in the binary (such as the irradiated surface or the stream-impact point), and their narrowness is due instead to the low inclination (?10°) of Ser X-1
Personal Papers (MS 80-0002)
No full textLetter from Isaac H. Kempner to Ray Bowen thanking for sending him the Annual Pass
Postcard, Jack H. Ray to Emmett L. Ray, December 20, 1937
No full textIn this handwritten postcard note, dated December 20, 1937, Jack H. Ray writes to his father, Emmett L. Ray to tell him how he\u27s getting along at his brother Leighton\u27s house in Santa Rosa, California. He describes what they\u27ve done, talks about his niece, and expresses that he\u27s glad he came.https://scholarsjunction.msstate.edu/mss-webb-collection/1623/thumbnail.jp
4-H, Sugar Ray : PSA 151
No full textA public service announcement about 4-H featuring boxing champion Sugar Ray Leonard
Letter, Jack H. Ray to Anna (Annie) Webb Ray, November 18, 1927
No full textIn this handwritten letter, dated November 18, 1927, Jack H. Ray writes to his mother, Anna (Annie) Webb Ray to explain how he hasn\u27t been able to go to class due to the inflammation in his eyes. He goes on to describe the trip he made to Alabama with the Senior Engineers and shares news from the Mississippi A & M College campus.https://scholarsjunction.msstate.edu/mss-webb-collection/1622/thumbnail.jp
[Letter from Alex Bradford to Lieutenant and Mrs. Ray Starner - November 4, 1940]
No full textLetter from Alex Bradford to Lieutenant and Mrs. Ray Starner describing the the current state of affairs that the author was experiencing, including: the London blitz, the moral of the troops on the ground, and the collective company of men opposing the Nazi regime
Letter, Jack H. Ray to Anna (Annie) Webb Ray, November 7, 1927
No full textIn this handwritten letter, dated November 7, 1927, Jack H. Ray writes to his mother, Anna (Annie) Webb Ray to let her know that he went home to visit them the day before but they were gone. He describes his travel from Starkville to Kosciusko by coal train. He goes on to describe the inflammation in his eyes and how he\u27s handling it as well as an accidental explosion in the chemical lab on the Mississippi A. & M. College campus and how the boys involved were more scared than hurt.https://scholarsjunction.msstate.edu/mss-webb-collection/1621/thumbnail.jp
Experimental Measurements and Computer Simulation of Fission Product Gamma-Ray Spectra
No full textAirborne gamma ray spectrometry using high volume scintillation detectors, optionally in conjunction with Ge detectors, has potential for making rapid environmental measurements in response to nuclear accidents. An experimental investigation and computer simulation have been used to characterise the response of such detectors to short lived fission products. Small samples of 235U were irradiated in a research reactor for short periods, to generate fission product sources. Gamma ray spectra were recorded over a period of one year using both high volume scintillation detectors and semiconductor detectors. The main gamma emitting nuclides have been identified, and their associated signals in each detector defined. Simulation work has been used to calculate the corresponding spectra which would have been observed at airborne survey heights, or from fission product sources irradiated for a prolonged period. While Ge detectors can record a fuller range of isotopes, of interest in characterising release terms, the NaI spectra also have potential for providing data on a range of radiologically important isotopes at all stages
Letter from H. L. Ray to L. S. Joynes, 1864 September 23
No full textLetter from H. L. Ray to L. S. Joynes asking about the process for attending the Medical College of Virginia.https://scholarscompass.vcu.edu/san/1091/thumbnail.jp
Relations between x-ray timing features and spectral parameters of galactic black hole x-ray binaries
No full textWe present a study of correlations between spectral and timing parameters for a sample of black hole X-ray binary candidates. Data are taken from GX
339-4, H 1743-322, and XTE J1650-500, as the Rossi X-ray Timing Explorer
(RXTE) observed complete outbursts of these sources. In our study we investigate outbursts that happened before the end of 2009 to make use of the high-energy coverage of the HEXTE detector and select observations that
show a certain type of quasi-periodic oscillations (type-C QPOs). The spectral parameters are derived using the empirical convolution model simpl to model the Comptonized component of the emission together with a disc blackbody for the emission of the accretion disc. Additional spectral features, namely a reflection component, a high-energy cut-off, and excess emission at 6.4 keV, are taken into account. Our investigations confirm the known positive
correlation between photon index and centroid frequency of the QPOs and reveal an anti-correlation between the fraction of up-scattered photons and the QPO frequency. We show that both correlations behave as expected in the “sombrero”
geometry. Furthermore, we find that during outburst decay the correlation between photon index and QPO frequency follow a general track, independent of individual outbursts
- …
