Please use this identifier to cite or link to this item: http://hdl.handle.net/10603/338926
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dc.date.accessioned2021-09-03T05:10:41Z-
dc.date.available2021-09-03T05:10:41Z-
dc.identifier.urihttp://hdl.handle.net/10603/338926-
dc.description.abstractClassification of different types of astronomical objects in large surveys usually done through spectroscopy requires enormous amounts of time. Hence, many attempts have been made using broad band photometric magnitudes and spectroscopic observations to classify the sources, particularly extragalactic sources such as active galactic nuclei (AGNs), starburst galaxies and newlinenormal galaxies. However, a method which does not involve spectroscopic data would be ideal. With this in view, in this work we have made an effort to classify a sample of 37,492 point sources into Quasi-Stellar Objects (QSOs), galaxies and stars using template fitting technique and multiwavelength photometric magnitudes from the Sloan Digital Sky Survey (SDSS) and newlinethe Galaxy Evolution Explorer (GALEX) with coverage from the optical (z: 8931 Å) to the far ultraviolet (FUV: 1516 Å). Templates for QSOs, galaxies and stars were used to fit the data of the objects to the seven photometric bands of SDSS and GALEX. The results were compared with SDSS spectroscopic classification. Two UV bands (NUV and FUV) were included to remove the possible degeneracies in the classification based only on optical bands or in color-color method. UV bands play a crucial role in the classification and characterization of astronomical objects that emit over a wide range of wavelengths, especially for those that are bright at UV. Classification using template fitting method is consistent with spectroscopic methods, provided UV information of the objects is available. UV bands are particularly important for separating quasars and stars, as well as spiral and starburst galaxies. We have achieved the efficiency of 89% for QSOs, 63% for galaxies and 84% for stars. Objects for which spectroscopic data is not available can also be classified using this method which does not require spectroscopic information.
dc.format.extentxv, 98p.;
dc.languageEnglish
dc.relationIEEE
dc.rightsuniversity
dc.titleClassification of extragalactic point sources and flux variability characteristics of blazars
dc.title.alternative
dc.creator.researcherAnjum, Ayesha
dc.subject.keywordAstronomy and Astrophysics space science
dc.subject.keywordPhysical Sciences
dc.subject.keywordSpace Sciences
dc.description.note
dc.contributor.guideGudennavar, Shivappa B
dc.publisher.placeBangalore
dc.publisher.universityCHRIST University
dc.publisher.institutionDepartment of Physics and Electronics
dc.date.registered2014
dc.date.completed2021
dc.date.awarded2021
dc.format.dimensionsA4
dc.format.accompanyingmaterialCD
dc.source.universityUniversity
dc.type.degreePh.D.
Appears in Departments:Department of Physics and Electronics

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01_title.pdfAttached File183.94 kBAdobe PDFView/Open
02_declaration.pdf34.6 kBAdobe PDFView/Open
03_certificate.pdf545.39 kBAdobe PDFView/Open
04_acknowledgements.pdf188.51 kBAdobe PDFView/Open
05_abstract.pdf132.46 kBAdobe PDFView/Open
06_contents.pdf82.88 kBAdobe PDFView/Open
07_list_of_figures.pdf121.41 kBAdobe PDFView/Open
08_list_of_tables.pdf41.21 kBAdobe PDFView/Open
09_chapter1.pdf166.76 kBAdobe PDFView/Open
10_chapter2.pdf175.5 kBAdobe PDFView/Open
11_chapter3.pdf2.5 MBAdobe PDFView/Open
12_chapter4.pdf540.68 kBAdobe PDFView/Open
13_chapter5.pdf159.57 kBAdobe PDFView/Open
14_bibliography.pdf94.23 kBAdobe PDFView/Open
15_publications_and_presentations.pdf142.7 kBAdobe PDFView/Open
80_recommendation.pdf335.64 kBAdobe PDFView/Open


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