GALEX FUV PDF

Leire Beitia-Antero and Ana I. Received: 18 November Accepted: 19 September However, due to brightness limits, the GALEX mission has avoided the Galactic plane which is crucial for astrophysical research and future space missions. Good quality spectra have been selected for the IUE classes of stellar sources. The sources in the catalogue are distributed over the full sky, including the Galactic plane.

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Leire Beitia-Antero and Ana I. Received: 18 November Accepted: 19 September However, due to brightness limits, the GALEX mission has avoided the Galactic plane which is crucial for astrophysical research and future space missions. Good quality spectra have been selected for the IUE classes of stellar sources. The sources in the catalogue are distributed over the full sky, including the Galactic plane.

Full Tables A. Moreover, the photometric database does not extend to bright UV sources that are ideally suited for calibration purposes.

Good quality spectra according to the criteria defined in Sect. Therefore NUV photometry can only be provided for non-variable sources. The database contains all data including overexposed or underexposed spectra as well as observations that suffered problems during the downlink, calibration, processing and other processes. To avoid including bad spectra in the photometric database, we removed from our list:. Within these windows we compute the mean flux and the dispersion. We reject the spectra if the mean flux is negative or if the standard deviation is ten times higher than the mean in any of the regions II-III-IV.

We allow for a factor of ten to prevent removing sources with steep energy distributions or strong features. The AB magnitude is calculated using Eq. To evaluate the NUV synthetic magnitude, it is first necessary to determine whether the sources are variable see Sect. After this, the spectrum is multiplied by the normalised transmittance of the NUV filter. In case there are multiple observations and the source is found not to vary, synthetic magnitudes are computed from the average flux.

For each spectrum and band, the Flux error provided by the mission Col. In case there are multiple observations and the source is found not to vary, errors are from the Flux errors. There are stars in the IUE archive with multiple observations in the SW range and stars with multiple observations in the LW range. For those, variability has been tested. Very noisy data have already been rejected in the data selection process see Sect. The procedure is similar to that described for the SW range but, in this case, the variability test is carried out only over the range of the NUV band contained in the LW images.

According to these criteria, 52 stars are found to be variable in the LW range and 88 in the SW range; only 36 stars are found to be variable in both ranges. An additional search for variable sources was carried out by comparing the fluxes in the window where SW and LW spectra overlap for every source. Three additional stars have been identified as variables from this test, namely HD , HD , and HD , and have been excluded from the catalogue.

We have used this subset to check the photometric accuracy of the synthetic magnitudes computed in this work see Table 1 for their synthetic and GALEX magnitudes. As shown in Fig. The coefficients of the fit, c 0 , c 1 , and c 2 , are given in Table 2. The catalogue contains FUV magnitudes for all stars with and without multiple observations and NUV magnitudes only for non-variable stars, or stars with just one good observation, as pointed out in Sect. Appendix A contains an excerpt of the catalogue available at the CDS.

For each source, the following entries are provided:. Object identification in the IUE Archive. Synthetic FUV magnitude Eq.

For the 88 stars found to be variable in the SW range, additional entries are provided in a supplementary catalogue an excerpt is shown in Appendix B with the FUV synthetic magnitude for each observation see Sect.

The following entries are provided:. The distribution of sources in the sky is plotted in Fig. A summary statistics of the catalogue contents is available in Table 4. This work adds UV photometry for new sources, most of them hot O-A spectral type stars. Table 2 Quadratic fit parameters for the WDs sample. Variable sources as per the criteria in Sect. Table 4 Catalogue contents.

See Gonzalez-Riestra et al. These sources are too weak to have been observed with IUE. An excerpt first ten entries of the catalogue is shown in Table A. The full catalogue is available at the CDS. Table A. The full table is available at the CDS.

Table B. Distribution in the sky of the sources in the catalogue. Data correspond to usage on the plateform after The current usage metrics is available hours after online publication and is updated daily on week days. Introduction 2. Consistency and spelling matters 3. Punctuation 4. Verb tense and voice 5. Nouns, articles, and adjectives 6. Structural concerns 7.

Clarity and precision 8. Free Access. Top Abstract 1. The IUE Methods 5. Photometric accuracy 6. The catalogue 7. Bianchi, L. In the text. Current usage metrics About article metrics Return to article. Initial download of the metrics may take a while. Previous article Next article. Metrics Show article metrics. Services Articles citing this article CrossRef 3. Bookmarking Mendeley. Reader's services Email-alert.

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The instrument is a 50 cm Ritchey-Chretien telescope with selectable imaging window or objective grism feeding a pair of detectors simultaneously with a multilayer dichroic beamsplitter. A cross section of the instrument is shown in Figure 2 below. The adopted design meets the challenging requirements of providing moderate-resolution optics with a high throughput and large field of view in four different optical paths two UV simultaneous channels, with imagery and slitless spectroscopy modes , while keeping the instrument compact and simple to build and adjust. As needed for a SMEX program, special attention was paid to keep the concept tolerant to component positioning, especially for the moveable parts. Its reflecting entrance side corrects the FUV channel, whereas the exit side cancels the entrance side effects and brings in the required amount of correction for the NUV channel. Allowance has been made for a small wedge on this aspheric window to compensate for the coma it induces in the NUV convergent beam. Its wedge angle is adjusted to correct for the coma induced in a converging beam, simultaneously for orders 2 and 1 spectra of the FUV and NUV channels respectively.

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Site Home Page. Cycle 6 Information. Field of View 1. Grism Rotation Grism position angle may be selected with a resolution of 0. Ion-etched fused silica aspheric surfaces on both sides.

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