Teff (K) Log  Teff(K) Log calibration for He I 10830 Teff(K) Log calibration for Hα Log calibration for Ca II IRT- a Analysis of chromospheric flux-flux relationships of M Dwarfs using visible and near-infrared CARMENES spectra F. Labarga1; D. Montes1; C. Duque-Arribas1; A. López-Gallifa1; J. A. Caballero2; S. V. Jeffers3; A. Reiners4; I. Ribas5; A. Quirrenbach6; P. J. Amado7; and the CARMENES Consortium 1 Dpto. Física de la Tierra y Astrofísica & IPARCOS-UCM (Instituto de Física de Partículas y del Cosmos UCM), Fac. CC Físicas, Univ. Complutense de Madrid, Spain 2 Centro de Astrobiología (CSIC - INTA), ESAC campus, camino bajo del castillo s/n, 28691, Villanueva de la Cañada, Madrid, Spain 3 Max Planck Institute for Solar System Research, Göttingen, Germany 4 Institut für Astrophysik, Georg-August-Universität, Göttingen, Germany 5 Institut de Ciències de l’Espai & IEEC-CSIC, Campus UAB, c/ de Can Magrans s/n, E-08193 Bellaterra, Barcelona, Spain 6 Zentrum für Astronomie der Universität Heidelberg, Landessternwarte, Heidelberg, Germany 7 Instituto de Astrofísica de Andalucía (IAA, CSIC), Glorieta de la Astronomía s/n, E-18008 Granada, Spain Fig. 1: Results of applying the spectral subtraction for selected chromospheric activity indicators (He I D3, Na I D1, D2, Hα and the first two of three Ca II IRT lines in the VIS) with the CARMENES spectra of J22468+443 (EV Lac) at the maximum level of chromospheric activity (Flare) and in a previous quiescent phase as well as the synthetic spectrum obtained with a M3.5 V reference star (J22096-046). The spectra to perform the subtraction are shown at the bottom and the obtained subtracted spectra at top from where we derived the EW of the chromospheric contribution. The algorithm makes use of the python code iSTARMOD as described in Labarga & Montes (2020). The spectral subtraction technique (Barden, SC; 1985, Montes et al., 2000) is well suited for the study of chromospheric activity in M-dwarfs, given that this type of stars does not have a well-defined continuum, especially in its late-types. The detailed analysis of the activity indicators is important from one side in order to confirm or discard all the possible planets around these stars and by the other studying its dependency with other stellar parameters as rotation, age and depth of the convective zone. This is the case for the stars of the CARMENES survey (Quirrenbach et al. 2020), where a WG on stellar activity, elaborating on its characterization in order to discount the jamming effect on stellar spectra of activity and rotation in the detection of exoplanet candidates. The CARMENES has the aim of detecting Earth-mass planets orbiting in the habitable zones of their host stars, focusing on over 300 M-type dwarf stars, spread over the complete M spectral range. For the work carried out in this study, the spectral subtraction technique (see Fig. 1) has been applied using the Python code iSTARMOD (Labarga & Montes, 2020). ABSTRACT: Exploiting the huge amount of data provided by the CARMENES survey, this work aims to study the chromospheric activity of M dwarfs based on a sub-sample (active RV-loud M dwarfs) of CARMENES GTO sample. Using the spectral subtraction technique and calibrations of the continuum-flux near the line of interest, the available information on the chromospheric activity flux is extracted. Most of the chromospheric indicators included in the spectral range of the spectrograph, ranging from visible (VIS) - that include the Na I D1&D2 He I D3, and Hα lines - to near-infrared (NIR) - that include the Ca II IRT, He I 10830, Paschenα and Paschenβ lines - are used. For the implementation of the spectral subtraction technique, a Python code (iSTARMOD) based on a previous FORTRAN one, formerly used by the research group, is used. The synthetic spectra for effective temperatures in the range [2400, 7000] K, allows through the calibrations a comparison of the flux-flux relationships with previous works performed