X-ray spectrum of the high polarization quasar PKS 1510-089

We present results on the X-ray spectra of the radio-loud, high-polarization quasar, PKS 1510-089, based on new data obtained using ASCA, and from archival ROSAT data. The X-ray spectrum obtained by ASCA is unusually hard, with the photon index=1.30+-0.06, while the (non-simultaneous) ROSAT data indicate a steeper spectrum (1.9+-0.3). The X-ray flux at 1 keV is within 10% during both observations. A break in the underlying continuum at about 0.7 keV is suggested. Flat X-ray spectra seem to be the characteristic of high polarization quasars, and their spectra also appear to be harder than that of the other radio-loud but low-polarization quasars. The multiwavelength spectrum of PKS 1510-089 is similar to many other gamma-ray blazars, suggesting the emission is dominated by that from a relativistic jet. A big blue-bump is also seen in its multiwavelength spectrum, suggesting the presence of a strong thermal component as well.Comment: 19 pages (Latex + 5 ps figures), Accpeted for publication in the Astrophysical Journal, December 20, 199

The Hard X-Ray Emission from Scorpius X-1 Seen by INTEGRAL

We present the results of our hard X-ray and gamma-ray study of the LMXB Sco X-1 utilizing INTEGRAL data as well as contemporaneous RXTE PCA data. We have investigated the hard X-ray spectral properties of Sco X-1 including the nature of the high-energy, nonthermal component and its possible correlations with the location of the source on the soft X-ray color-color diagram. We find that Sco X-1 follows two distinct spectral tracks when the 20-40 keV count rate is greater than 130 counts/second. One state is a hard state which exhibits a significant high-energy, powerlaw tail to the lower energy thermal spectrum. The other state shows a much less significant high-energy component. We found suggestive evidence for a correlation of these hard and soft high-energy states with the position of Sco X-1 on the low-energy X-ray color-color diagram. We have searched for similar behavior in 2 other Z sources: GX 17+2 and GX 5-1 with negative results

Mass Determination of Black Holes in LMC X-1 and Nova Muscae 1991 from their High-Energy Spectra

We offer a brief description of the bulk-motion Comptonization (BMC) model for accretion onto black holes, illustrated by its application to observational data for LMC X-1, and Nova Muscae 1991. We then extract some physical parameters of these systems from observables (within the context of the BMC model}, drawing from results on GRO J1655-40, for which we presented extensive analysis previously. We derive estimates of the mass, (16 +/- 1) solar masses and mass accretion rate in the disk in Eddington units around 2 for LMC X-1, and (24 +/- 1)d_{5.5} and the disk mass acretion rate around 3 for Nova Muscae 1991 [where d_{5.5} stands for the distance in 5.5 kpc units]. Differences between these estimates and previous estimates based on dynamical studies are discussed. It is further shown that the disk inner radius increases with the high-to-low state transition in Nova Muscae 1991. Specifically, our analysis suggests that the inner-disk radius increases to 17 Scwarzschild radii as the transition to the low-hard state occurs.Comment: 14 pages, 3 figures, The paper is accepted for publication in the Astrophysical Journal Letter

Productivity levels of some Iowa soils

This report presents crop yield estimates for corn, soybeans, oats, and hay on 290 selected soil types and phases. These yield estimates are believed attainable as a 5-year average with the technology available in 1971 and average weather conditions.https://lib.dr.iastate.edu/specialreports/1063/thumbnail.jp

Simultaneous IUE, EXOSAT and optical observations of the unusual AM Her type variable H058+608

Simultaneous observations of the AM Her type variable H0538+608 made with IUE, EXOSAT, and a 1.3 m ground based telescope, and subsequent optical spectrophotometry at high and low resolution are discussed. The X-ray and optical data show clear evidence of a 3.30 + or - 0.03 hr period. Three SWP spectra were taken outside of eclipse and during overlapping phase intervals. The UV spectra contain strong emission lines characteristic of this class of objects and a flat continuum which appears to be deficient, given the brightness of source at optical and X-ray wavelengths. There is evidence for intensity variations in emission lines, particularly C IV. The X-ray light curves for H0538+608 reveal behavior which may be related to irregularities in its accretion flow

INTEGRAL Observations of the Pulsar PSR J1846-0258

We present the results of a study of the high-energy properties of PSR J1846-0258 using INTEGRAL data PSR J1846-0258 has a period of 325 ms and is embedded within a PWN that is associated with the SNR KES 75. This pulsar is unusual for two reasons. First, like Geminga, no radio pulsations have yet been detected from this pulsar. It has thus far been detected exclusively in the X-ray and gamma-ray bands. Second, it has a large inferred magnetic field, approx. 5 x 10(exp 13) G. The 20-200 keV spectra derived from 2.35 Msec of INTEGRAL IBIS/ISGRI observations are consistent with an extension of the previous spectral results at energies below 10 keV from Chandra. The possibility of detecting PSR J1846-0258 with GLAST is discussed as well as the implications a GLAST detection would have on pulsar theory, specifically photon splitting In the magnetospheres of high-field pulsars