Professor Ranjan Gupta

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Author: search.filters.author.Gupta, RanjanSubject: search.filters.subject.Infrared

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    A Near-Infrared Stellar Spectral Library: II. K-Band Spectra
    (Bull. Astr. Soc. India, 2007-05-31) Ranade, Ranade C; Singh, Harinder P.; Gupta, Ranjan; et
    This paper is the second in the series of papers on near-infrared (NIR) stellar spectral library produced by reducing the observations carried out with 1.2 meter Gurushikhar Infrared Telescope (GIRT), at Mt. Abu, India using a NICMOS3 HgCdTe 256×256 NIR array based spectrometer. In paper I (Ranade et al. 2004), H-band spectra of 135 stars at a resolution of 16°A were presented. The K-band library being released now consists of 114 stars covering spectral types O7–M7 and luminosity classes I–V. The spectra have a moderate resolution of 22°A in the K band and have been continuum shape corrected to their respective effective temperatures. We hope to release the remaining J-band spectra soon. The complete H and K-Band library
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    AUTOMATED CLASSIFICATION OF 2000 BRIGHT IRAS SOURCES
    (The Astrophysical Journal Supplement Series, 2004-06-25) Gupta, Ranjan; Singh, Harinder P.; Volk, K.; et.al
    An artificial neural network (ANN) scheme has been employed that uses a supervised back-propagation algorithm to classify 2000 bright sources from the Calgary database of Infrared Astronomical Satellite (IRAS) spectra in the region 8–23 m. The database has been classified into 17 predefined classes based on the spectral morphology. We have been able to classify over 80% of the sources correctly in the first instance. The speed and robustness of the scheme will allow us to classify the whole of the Low Resolution Spectrometer database, containing more than 50,000 sources, in the near future. Subject headings: infrared: galaxies — methods: data analysis