STELLA meets RAVE: Calibrating low-resolution Ca II IRT fluxes S.P. Järvinen, G. Kordopatis, K.G. Strassmeier, & M. Steinmetz Leibniz-Institut für Astrophysik Potsdam (AIP), Germany

RAVE Survey

RAVE ( Experiment) is a multi-fiber spectroscopic astronomical survey of stars in the using the 1.2-m UK Schmidt Telescope of the Australian Astronomical Observatory (AAO). In between 2003 and 2013 in total 574,630 low-resolution (R = λ/∆λ ∼ 7, 500) spectra of 483,330 stars covering the Ca II infrared triplet (IRT) has been obtained. The fourth data release (Kordopatis et al. 2013 AJ, 146, 134) contains the stellar atmospheric parameters (, surface gravity, overall ), radial velocities, individual abundances, and distances determined for 425,561 stars. Furthermore, a catalog of chromospherically active stars has been constructed (Žerjal et al. 2013 ApJ, 776, 127).

www.rave-survey.org

Distribution of RAVE stars on the sky, colour-coded by stellar heliocentric velocity.

By numbers STELLA follow up of late-type dwarfs STELLA (STELLar Activity) are two fully robotic, 1.2m telescope at Izana Over 95,000 individual RAVE spectra have such stellar parameters Observatory located in Tenerife, Spain. Follow up is done with STELLA échelle that they can be considered as late-type dwarfs. spectrograph (SES), which is a modern white-pupil spectrograph with a spectral After sweeping out obvious bad spectra as well as some binaries, we resolution of about 55,000 and a fixed wavelength format from 390 to 870nm. still end up with ~88,000 spectra IRT−1 IRT−2 IRT−3 ~14,000 dwarfs have detectable emission features (Žerjal et al. 2013 1.0 1.0 1.0 ApJ, 776, 127) 0.9 0.9 0.9 0.8 0.8 0.8

0.7 0.7 0.7

IRT fluxes 0.6 0.6 0.6 Normalized flux Normalized flux Normalized flux

0.5 STELLA 0.5 STELLA 0.5 STELLA RAVE RAVE RAVE 0.4 0.4 0.4

We measure the relative flux in the inner 1-Å portion for each of the 8490 8492 8494 8496 8498 8500 8502 8504 8530 8535 8540 8545 8550 8555 8640 8650 8660 8670 8680 Wavelength [Å] Wavelength [Å] Wavelength [Å] three IRT lines Comparison of RAVE and STELLA spectra. These fluxes are then related to the absolute continuum flux, FC, pre- computed for the IRT wavelengths. The latter are obtained from the IRT1 IRT2 IRT3 relations provided by Hall (1996, PASP, 108, 313). 6.8 6.8 6.8

6.6 6.6 6.6 The emission-line fluxes in erg cm−2 s−1 are then derived from the 6.4 6.4 6.4 measured 1-Å equivalent width of the line, WIRT: FIRT = (WIRT/WC)FC. 6.2 6.2 6.2

C is based on the color index B−V from the conversion of Teff with the log F (RAVE) log F (RAVE) log F (RAVE) F 6.0 6.0 6.0 colour transformation from Flower (1996 ApJ, 469, 355). 5.8 5.8 5.8

5.8 6.0 6.2 6.4 6.6 6.8 5.8 6.0 6.2 6.4 6.6 6.8 5.8 6.0 6.2 6.4 6.6 6.8 log F (SES) log F (SES) log F (SES)

7.0 7.0 7.0 SES versus RAVE flux relationships for each of the Ca II IRT lines. 6.8 6.8 6.8 6.6 6.6 6.6 6.8 6.8 6.8 6.4 6.4 6.4 6.6 6.6 6.6 6.2 6.2 6.2 6.4 6.4 6.4

log F (IRT1) 6.0 log F (IRT2) 6.0 log F (IRT3) 6.0 5.8 5.8 5.8 6.2 6.2 6.2

6.0 6.0 6.0

0.2 0.4 0.6 0.8 1.0 1.2 1.4 0.2 0.4 0.6 0.8 1.0 1.2 1.4 0.2 0.4 0.6 0.8 1.0 1.2 1.4 log F (Halpha) log F (H alpha) log F (H alpha) B−V B−V B−V 5.8 5.8 5.8

5.6 5.6 5.6

5.8 6.0 6.2 6.4 6.6 6.8 5.8 6.0 6.2 6.4 6.6 6.8 5.8 6.0 6.2 6.4 6.6 6.8 Ca II IRT surface flux vs colour index B−V from RAVE spectra. Relations by Hall (1996) log F (IRT1) log F (IRT2) log F (IRT3) cover temperature range 4153-7766K. Flux-flux relationships between Ca II IRT lines and Hα line based on SES spectra.

SPJ acknowledges support from Deutsche Forschungsgemeinschaft, DFG project number JA 2499/1-1.

CoolStars19, Uppsala, Sweden