Description of libraries
This web application has been developed to give an access to spectra and stellar atmospheric
parameters of three stellar libraries — UVES-POP, INDO-US, and LCO-SL.
Here we give a brief information on each of the libraries.
UVES-POPThe first version library was released in 2003 (Bagnulo et al., 2003) and contained optical spectra of about 400 stars with the resolving power of R=80,000 collected with the UVES spectrograph at ESO VLT. The new release consists of spectra of 406 stars, has the wavelength coverage 3200 Å < λ < 10250 Å and is available at two resolving powers of R=80,000 and R=20,000. All stars were observed with UVES using a 0.5"-wide slit. We re-reduced raw UVES-POP spectra from the ESO data archive with the 2018 version of the UVES pipeline and some additional algorithms that we developed to correct artifacts, which were present in the original UVES-POP release. The most significant improvements in comparison with the original UVES-POP library are: (i) the improved merging of Echelle orders which eliminates “ripples” present in the original spectra by correctly accounting for scattered light and blaze shift between flat field and science exposures; (ii) full telluric absorption correction; (iii) merging of non-overlapping UVES spectral setups which preserves the global continuum shape; (iv) spectrophotometric correction and absolute flux calibration with use of 33 middle- and broad-band photometry including several ground-based datasets plus Gaia and Tycho data. We also estimated the E(B-V) values for all stars from the library. The overall final absolute flux uncertainty is better than 1.5-2% for over half of the sample, 2-3% for about a quarter, and better than 4% for the remaining 100 stars.
INDO-USThe original data release of the INDO-US library took place in 2004 (Valdes et al., 2004). This library contains spectra of 1273 stars obtained using the 0.9-m Coude feed telescope at Kitt Peak National Observatory. Spectra cover the wavelength range from 3460 to 9464 Å and have a spectral resolution of about 1 Å. Here we present a completely re-calibrated data for INDO-US stars. We started from baseline-calibrated spectra in individual observing setups (6 setups covering the entire optical wavelength range). We re-designed the telluric correction and flux calibration with the use of the spectrophotometric correction algorithm and also improved the wavelength calibration and, finally, brought all the spectra into the restframe.
LCO-SLStars of the LCO-SL were observed in 2013-2017 by our team using the FIRE spectrograph mounted on the 6.5-m Magellan-Baade Telescope in the Las Campanas Observatory. This unique library is the most comprehensive near-infrared spectral library — it includes spectra of more than 1300 stars covering very different regions of the HR diagram. The most valuable data in LCO-SL are spectra of asymptotic giant branch (AGB) stars which is the largest sample of these stars up-to-date. Besides that, the library includes spectra of 35 stars from LMC and SMC, 20 stars from the Galactic bulge, and about 80 red giants from Galactic globular clusters covering the metallicity range between -2.2 and -0.3 dex. Additionally, it contains (i) spectra of 8 bright L/T dwarfs including the 3rd nearest star to the Sun, the binary brown dwarf Luhman 16 (spectra of both components are available separately), (ii) 20 chemically peculiar A stars, and (iii) 5 planets/satellites of the Solar system -- Mars, Jupiter, Saturn, Titan, and Uranus. Having the wavelength coverage between 8450 Å and 25000 Å at the spectral resolving power of R=6500, the library is an invaluable component of the stellar population modeling in the NIR.
At this page we present the data reduction pipelines for the intermediate-resolution (R=5000-10000) slit echelle spectographs MagE and FIRE mounted on the 6.5-m Magellan Baade telescope at the Las Campanas Observatory). The pipelines are implemented in IDL and share about 80% of the code. The final data products are sky subtracted flux calibrated two-dimensional spectra corrected for telluric absorption. More details on the pipelines you can find in the paper by Chilingarian et al. (2020).
The latest version of the pipelines can be found here. It is updated as the code evolves.
Pipeline requirementsWe defined the following set of requirements for the new pipelines:
- Possibility to use only day-time calibrations (flats + arcs + skyflats)
- 2D slit output (ID extracted spectra are optional)
- Homogeneous output: (i) constant R=6500 for FIRE 0.45” slit; (ii) no R variations along echelle orders
- Wavelength calibration uncertainties: 2-3 km/s
- Flux calibration uncertainties: (i) FIRE global <3% in the range 0.83-2.5 μm, local <0.5% in 200 nm windows; (ii) MagE global <5% at 0.35-0.95 μm, local <1.5% within each order; (iii) MagE fringing correction <2% at 0.9 μm
- Telluric absorption correction <2% in the areas where transmission is >50%
- IDL with minimal dependencies: NASA Goddard astrolib, mpfit
- Open source (GPL), git access (bitbucket)
- All calibration files are included in the package
- Execution time <10min per object on a laptop/desktop produced in 2014-15