Subscribe to the gold package and get unlimited access to Shamra Academy
Register a new userInitial results from SECIS observations of the 2001 eclipse
97
0
0.0
(
0
)
Added by
Athanassios Katsiyannis
Publication date
2003
fields
Physics
and research's language is
English
Ask ChatGPT about the research
No Arabic abstract
SECIS observations of the June 2001 total solar eclipse were taken using an Fe xiv 5303 A filter. Existing software was modified and new code was developed for the reduction and analysis of these data. The observations, data reduction, study of the atmospheric and instrumental effects, together with some preliminary results are discussed. Emphasis is given to the techniques used for the automated alignment of the 8000 images, the application of the a Trous algorithm for noise filtering and the software developed for the automated detection of intensity oscillations using wavelet analysis. In line with findings from the 1999 SECIS total eclipse observations, intensity oscillations with periods in the range of 20-30 s, both inside and just outside coronal loops are also presented.
rate research
Read More
SECIS observations of the June 2001 total solar eclipse were taken using an Fe {sc xiv} 5303 {AA} filter. Automated tools based on wavelet analysis was used to detect intensity oscillations on various areas of the images. Statistical analysis of the detections found in the areas covered by the moon and the upper corona allowed us to estimate the atmospheric and instrumental effects on the detection of intensity oscillations. An area of the lower corona, close to Active Region 9513, was found with a statistically significant amount of intensity oscillations with periodicity of $sim7.5s$. The shape of the wavelet transformation of those detections matches theoretical predictions of sausage-mode perturbations and for the first time in the SECIS project, second order oscillations were also detected.
8000 images of the Solar corona were captured during the June 2001 total Solar eclipse. New software for the alignment of the images and an automated technique for detecting intensity oscillations using multi scale wavelet analysis were developed. Large areas of the images covered by the Moon and the upper corona were scanned for oscillations and the statistical properties of the atmospheric effects were determined. The a Trous wavelet transform was used for noise reduction and Monte Carlo analysis as a significance test of the detections. The effectiveness of those techniques is discussed in detail.
Results are presented for an initial survey of the Norma Arm gathered with the focusing hard X-ray telescope NuSTAR. The survey covers 0.2 deg$^2$ of sky area in the 3-79 keV range with a minimum and maximum raw depth of 15 ks and 135 ks, respectively. Besides a bright black-hole X-ray binary in outburst (4U 1630-47) and a new X-ray transient (NuSTAR J163433-473841), NuSTAR locates three sources from the Chandra survey of this region whose spectra are extended above 10 keV for the first time: CXOU J163329.5-473332, CXOU J163350.9-474638, and CXOU J163355.1-473804. Imaging, timing, and spectral data from a broad X-ray range (0.3-79 keV) are analyzed and interpreted with the aim of classifying these objects. CXOU J163329.5-473332 is either a cataclysmic variable or a faint low-mass X-ray binary. CXOU J163350.9-474638 varies in intensity on year-long timescales, and with no multi-wavelength counterpart, it could be a distant X-ray binary or possibly a magnetar. CXOU J163355.1-473804 features a helium-like iron line at 6.7 keV and is classified as a nearby cataclysmic variable. Additional surveys are planned for the Norma Arm and Galactic Center, and those NuSTAR observations will benefit from the lessons learned during this pilot study.
WZ Sge has shown superoutbursts in 1913, 1946 and 1978. On 2001 July 23 a new outburst was announced, about 10 years `too early. Target of opportunity satellite observations with Chandra, FUSE, HST and RXTE were performed throughout the outburst. From the ground WZ Sge was monitored by numerous professional and amateur astronomers, in the optical, IR and radio. We give an account of the first exciting results from these multi-wavelength observations.
We discuss the measurements of the main parameters of the ionospheric response to the total solar eclipse of June 21, 2001. This study is based on using the data from three stations of the global GPS network located in the area of the totality band in Africa. This period was characterized by a low level of geomagnetic disturbance (the Dst-index varied from -6 to 22 nT), which alleviated greatly the problem of detecting the ionospheric response to eclipse. An analysis revealed a clearly pronounced effect of a decrease (depression) of the total electron content (TEC) for all GPS stations. The delay between the smallest value of the TEC with respect to eclipse totality was 9-37 min. The depth and duration of the TEC depression were 0.5-0.9 TECU and 30-67 min, respectively. The results obtained in this study are in good agreement with earlier measurements and theoretical estimations.
Log in to be able to interact and post comments
comments
Fetching comments
Sign in to be able to follow your search criteria
