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Chicago, Burlington & Quincy (CBQ) 2942
No full textA photograph print showing Chicago, Burlington & Quincy (CBQ) 2942, 4-6-2, Class S-2, Chicago, IL
Block Card 2942 Meadowwood Drive
No full textThis image was produced by the Auditor's Office in Lucas County, Ohio for tax assessment purposes. Associated dates are approximate. Descriptive terms related to this photograph include: English Cottage Style | 2942 Meadowwood Drive (Toledo, Ohio) | Dwelling | Old Orchard Addition (Toledo, Ohio) | Old Orchard Area (Toledo, Ohio
Multiwavelength observations of the black hole candidate 1E 1740.7-2942
No full textObservations of the Galactic center region black hole candidate
1E 1740.7-2942 have been carried out using the Caltech Gamma-Ray Imaging Payload
(GRIP), the Röntgensatellit (ROSAT) and the Very Large Array (VLA). These
multiwavelength observations have helped to establish the association between a
bright emitter of hard X-rays and soft γ-rays, the compact core of a double radio jet
source, and the X-ray source, 1E 1740.7-2942. They have also provided information
on the X-ray and hard X-ray spectrum.
The Galactic center region was observed by GRIP during balloon flights from
Alice Springs, NT, Australia on 1988 April 12 and 1989 April 3. These observations
revealed that 1E 1740.7-2942 was the strongest source of hard X-rays within ~10°
of the Galactic center. The source spectrum from each flight is well fit by a single
power law in the energy range 35-200 keV. The best-fit photon indices and 100 keV
normalizations are: γ = (2.05 ± 0.15) and K_(100) = (8.5 ± 0.5) x 10^(-5) cm^(-2) s^(-1) keV^(-1)
and γ = (2.2 ± 0.3) and K_(100) = (7.0 ± 0.7) x 10^(-5) cm^(-2) s^(-1) keV^(-1) for the 1988 and
1989 observations respectively. No flux above 200 keV was detected during either
observation. These values are consistent with a constant spectrum and indicate that
1E 1740.7-2942 was in its normal hard X-ray emission state. A search on one hour
time scales showed no evidence for variability.
The ROSAT HRI observed 1E 1740.7-2942 during the period 1991 March
20-24. An improved source location has been derived from this observation. The
best fit coordinates (J2000) are: Right Ascension = 17^h43^m54^s.9, Declination =
-29°44'45".3, with a 90% confidence error circle of radius 8".5. The PSPC observation
was split between periods from 1992 September 28- October 4 and 1993 March
23-28. A thermal bremsstrahlung model fit to the data yields a column density of
N_H = 1.12^(+1.51)_(0.18) x cm^(-2) , consistent with earlier X- ray measurements.
We observed the region of the Einstein IPC error circle for 1E 1740.7-2942
with the VLA at 1.5 and 4.9 GHz on 1989 March 2. The 4.9 GHz observation revealed
two sources. Source 'A', which is the core of a double aligned radio jet source (Mirabel
et al. 1992), lies within our ROSAT error circle, further strengthening its identification
with 1E 1740.7-2942.</p
Observations of 1E 1740.7-2942 with ROSAT and the VLA
No full textWe have observed the Galactic black hole candidate 1E 1740.7-2942 in X-rays with both the ROSAT high resolution imager (HRI) and position-sensitive proportional counter (PSPC) and at 1.5 and 4.9 GHz with the very large array (VLA). From the HRI observation we derive a position for 1E 1740.7-2942 of right ascension = 17h 43m 54.9s, declination = -29 deg 44 min 45.3 sec (J2000), with a 90% confidence error circle of radius 8.5 sec. Thermal bremsstrahlung fits to the PSPC data yield a column density of 1.12 + 1.51 or -0.18 X 10^23/ sq cm, consistent with earlier X-ray measurements. The VLA observations of 4.9 GHz revealed two sources. Source A, which is the core of a double aligned radio jet source (Mirabel et al. 1992), lies within the ROSAT error circle, further confirming its identification with 1E 1740.7-2942
Warfield, Joshua Dorsey, 1838-1914 (SC 2942)
No full textFinding aid and full text scan (Click on Additional Files below) for Manuscripts Small Collection 2942. “The Gaithers of South River,” undated typescript by J. D. Warfield relating the history and genealogy of the Gaither family of Maryland and Kentucky. Includes a cover letter to the recipient and a bookplate of Edgar H. Gaither
[Atchison, Topeka, and Santa Fe, Diesel Electric Road Switcher No. 2942]
No full textNegative sleeve: 82:232:3958; [typed] Atchison, Topeka & Santa Fe, #2942 [Everett DeGolyer, Jr.'s Notes] Left side of train, photographed, showing 3/4 view of engine. Close-up, clear and sharp. Locomotive No. 2942 is a Diesel Electric Road Switcher, 2900 class locomotive, with a B-B wheel arrangement. No. 2942 was built by the General Motors Corporation, Electro-Motive Division, as a Model No. GP-9, and was originally made as No. 742, a 700 class locomotive
Going Beyond Counting First Authors in Author Co-citation Analysis
No full textThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
On the multiwavelength spectrum of the microquasar 1E1740.7-2942
No full textThe microquasar 1E 1740.7-2942 is a source located in the direction of the Galactic Center. It has been detected at X-rays, soft gamma-rays, and in the radio band, showing an extended radio component in the form of a double-sided jet. Although no optical counterpart has been found so far for 1E 1740.7-2942, its X-ray activity strongly points to a galactic nature. Aims.We aim to improve our understanding of the hard X-ray and gamma-ray production in the system, exploring whether the jet can emit significantly at high energies under the light of the present knowledge. Methods.We have modeled the source emission, from radio to gamma-rays, with a cold-matter dominated jet model. INTEGRAL data combined with radio and RXTE data, as well as EGRET and HESS upper-limits, are used to compare the computed and the observed spectra. Results.From our modeling, we find out that jet emission cannot explain the high fluxes observed at hard X-rays without violating at the same time the constraints from the radio data, favoring the corona origin of the hard X-rays. Also, 1E 1740.7-2942 might be detected by GLAST or AGILE at GeV energies, and by HESS and HESS-II beyond 100 GeV, with the spectral shape likely affected by photon-photon absorption in the disk and corona photon fields
On the multiwavelength spectrum of the microquasar 1E 1740.7-2942
No full textContext. The microquasar 1E 1740.7-2942 is a source located in the direction of the Galactic Center. It has been detected at X-rays, soft gamma-rays, and in the radio band, showing an extended radio component in the form of a double-sided jet. Although no optical counterpart has been found so far for IE 1740.7-2942, its X-ray activity strongly points to a galactic nature.
Aims. We aim to improve our understanding of the hard X-ray and gamma-ray production in the system, exploring whether the jet can emit significantly at high energies under the light of the present knowledge.
Methods. We have modeled the source emission, from radio to gamma-rays, with a cold-matter dominated jet model. INTEGRAL data combined with radio and RXTE data, as well as EGRET and HESS upper-limits, are used to compare the computed and the observed spectra.
Results. From our modeling, we find out that jet emission cannot explain the high fluxes observed at hard X-rays without violating at the same time the constraints from the radio data, favoring the corona origin of the hard X-rays. Also, 1E 1740.7-2942 might be detected by GLAST or AGILE at GeV energies, and by HESS and HESS-II beyond 100 GeV, with the spectral shape likely affected by photon-photon absorption in the disk and corona photon fields.Facultad de Ciencias Astronómicas y Geofísica
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