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S. Mereghetti G. F. Bignami P. A. Caraveo A. Goldwurm G. G. C. Palumbo 《Space Science Reviews》1985,40(3-4):495-501
A new EXOSAT (LE/CMA) observation of the region in Crux (R.A. 11h 45m, Dec. -62°) where Markert et al. (1981) reported the existence of two x-ray SNR's is presented. After cleaning the CMA field from the point source component, due to the UV emission of the numerous stars in the field, the smoothed x-ray contours are compared to the 408 MHz radio map of Caswell et al. (1983). The existence of two, well-separate x-ray emission regions is confirmed by EXOSAT, and the current x-ray/radio picture is not sufficent to distinguish clearly between the assumption of one or two (possibly interacting) SNR's in the region. 相似文献
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L. Vigroux J. A. Paul P. Delache G. F. Bignami P. A. Caraveo L. Salotti 《Space Science Reviews》1985,40(1-2):91-97
Einstein and EXOSAT data on the soft X-ray source IE 0630+178, the proposed counterpart of the -ray source GEMINGA, are analyzed for variability on the time scale of one to three hours. The EXOSAT September 1983 data, with an uninterrupted strech of over 10 hours offer the most interesting case. In parallel, a similar analysis is presented for the first time, for the optical data of the mV21 proposed counterpart. About 30 CCD exposures, of 15 min. each, taken over two consecutive nights at the 3.6 m CFH telescope, yield evidence of variability, when compared to the data of similar nearby objects in the field.Visiting astronomer at the Canada-France-Hawaii Telescope, operated by the National Concil of Research, Canada, the Centre National de la Recherche Scientifique, France, and the University of Hawaii. 相似文献
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S. Mereghetti P. Caraveo G. F. Bignami 《Advances in Space Research (includes Cospar's Information Bulletin, Space Research Today)》1993,13(12):343-346
We have re-analyzed the archive Einstein IPC and EXOSAT CMA x-ray data of Geminga, in the light of the recent discoveries on this source. The results of a search for the 237 msec periodicity are consistent with a pulsed fraction decreasing with x-ray energy. We have combined the EXOSAT CMA and the Einstein data in order to limit the spectral parameters allowed by the IPC fit. This joint analysis confirms that the spectrum cannot be described by a single temperature blackbody component. 相似文献
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Patrizia A. Caraveo 《Space Science Reviews》1983,36(3):207-221
The Einstein X-ray Imaging Instruments have been used to explore, down to an unprecedented sensitivity, the X-ray behavior of 7 high-energy γ-ray sources discovered by the COS-B satellite. 32 low latitude (¦b¦ < 5°) IPC fields, mosaic-arranged to cover the few-square-degrees COS-B error circles, yielded 30 soft X-ray sources, the fluxes of which range from ~ 1/100 to few UFU, and no diffuse features. While the density of ~ 1 source/IPC field is consistent with the value found at higher latitudes, the percentage of ‘stellar’ identifications among these low-latitude sources is significantly higher than in non-galactic-biased samples. Unfortunately, the positional accuracy achieved with the IPC does not allow astronomical identification in the absence of obvious counterpart(s). However, after the exploratory coverage, the IPC data were used, when possible, to point out potentially interesting targets for the HRI instrument capable of an accuracy of ~ 3 arc sec. Due to the misfortunes which occurred to the Einstein satellite, this time-consuming process was feasible only in two cases: within the error circle of 2CG135 + 01, the radio variable star LSI61.303 was pinpointed by the HRI, while the HRI exposure of the brightest X-ray source discovered in 2CG 195 + 04 (Geminga) positioned a source in an empty POSS field. The latter case will be presented and the nature of the X- and γ(?)-ray source briefly discussed. 相似文献
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P.A. Caraveo G.F. Bignami L. Vigroux J.A. Paul R.C. Lamb 《Advances in Space Research (includes Cospar's Information Bulletin, Space Research Today)》1984,3(10-12)
Dedicated X-ray, optical and radio observations aimed at the identification of the bright γ-ray source 2CG195+04 (GEMINGA) are presented. A very promising candidate is found and its properties are discussed in the context of possible astrophysical scenarios. 相似文献
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Optical data taken in January 1987 from La Silla, when compared with the discovery plate of 1975.2 show no proper motion for PSR 0833-45, while a very significant one was expected if the pulsar originated in the center of the Vela SNR, which has so far been associated with it. If such an association is to be retained, either an extreme asymmetry of the SNR is required, or both objects are much older than has so far been thought. Both alternatives have their difficulties, thus possibly casting doubts on the reality of this classic SNR/pulsar association.Based on observations collected at the European Southern Observatory, La Silla, Chile. 相似文献
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