Spectral Archive of Hot Galactic Supergiants (TCO Node)

This resource provides a digital archive of one-dimensional (1D) optical spectra of hot galactic supergiants, obtained at the Three College Observatory (TCO). The archive is integrated into the Kazakhstan National Virtual Observatory (KazVO) data services and optimized for the IVOA Simple Spectral Access Protocol (SSAP).

Data Specification:

• Data Type: Medium-resolution optical echelle spectra.
• File Format: FITS (Flexible Image Transport System).
• Data Representation: 1D merged (stitched) spectra.
• Flux Calibration: Relative intensity, normalized to the continuum.

Observational Setup and Instrumentation:

• Observatory: Three College Observatory (TCO), North Carolina, USA
• Telescope: 0.81-m Ritchey-Chretien telescope
• Instrument: Fiber-fed echelle spectrograph eShel
• Spectrograph Manufacturer: Shelyak Instruments

Spectral Characteristics:

• Spectral Range: Approximately 3900 - 7800 Angstroms (precise wavelength boundaries are frame-dependent and fixed within individual FITS headers).
• Spectral Resolution: R approx 12,000.
• Wavelength Calibration: Executed using a Thorium-Argon (ThAr) reference lamp spectrum.

Data Reduction Pipeline:

Primary and scientific data reduction was performed within the IRAF (Image Reduction and Analysis Facility) environment using standard echelle spectroscopy packages.

Key Reduction Steps:

1. Pre-processing: Bias frame subtraction.
2. Extraction: Localization and extraction of individual echelle orders.
3. Dispersion Relation: Wavelength calibration based on ThAr reference frames.
4. Order Merging: Stitching of discrete spectral orders into a continuous 1D array.
5. Kinematic Correction: Application of the heliocentric velocity correction (documented under the VHELIO FITS header keyword).
6. Continuum Normalization: Continuum flattening achieved via high-order polynomial fitting.

• stellar-spectroscopy
• Supergiant stars
• echelle-spectroscopy
• hot-stars

• Danford, S.
• Miroshnichenko, A.