High resolution spectroscopy of near infrared hydrogen lines in T Tauri stars is not commonly found in the literature. The only publication based on data with spectral resolution and signal-to-noise ratio comparable to those of the data presented in this work is Najita, Carr & Tokunaga (1996). These authors present Br Gamma line profiles for five T Tauri stars (DG Tau, AS 353A, V1331 Cyg, AS 205A and S CrA), one Class I source (SVS 13) and one low luminosity embedded object (WL 16), of which only two objects are in the sample presented here (DG Tau and V1331 Cyg). The Br Gamma line profiles shown by Najita et al. for both DG Tau and V1331 Cyg are very similar to the ones reported in this work (compare Figure 1 in Najita et al. with the Br Gamma lines of DG Tau and V1331 Cyg presented in Figure 5.2). The Br Gamma line profiles from the remaining objects presented in Najita et al. have shapes similar to the typical profiles presented here. Hamann, Simon & Ridgway (1988) present high resolution, but relatively low signal-to-noise, Br Gamma spectra of DG Tau, GW Ori, HL Tau, SU Aur and T Tau, all of which are in the sample studied here. Despite the low signal-to-noise ratio, it can be seen that the line profiles displayed in their Figure 1 have the same characteristics of the ones presented here. Even SU Aur, seen with a slightly redshifted absorption feature, is somewhat similar to the one shown in Figure 5.2. Comparison with other published line profiles than the ones mentioned above is very difficult due to the much lower spectral resolutions and signal-to-noise ratios. Examples of those are the data shown in Giovanardi et al. (1991) and Evans et al. (1987) where the line profiles are defined by only a few spectral points.
Trying to understand how the hydrogen emission lines in T Tauri stars arise does not rely solely on the study of line profiles. In the near infrared, important work has been carried out concentrating on the prediction and analysis of line fluxes and line ratios [Natta et al. 1988,Alonso-Costa & Kwan 1989,Carr 1990,Giovanardi et al. 1991, amongst others]. The set of data presented here does not allow one to compute line fluxes given that photometric template stars were not observed. In principle, the observed equivalent widths could be used together with broad band photometric data available in the literature for the T Tauri stars to determine total line fluxes. However, variability in the NIR magnitudes is observed in T Tauri stars, not allowing that method to be used unless the photometric data were simultaneous with the high resolution data. Such photometric data does not exist for the line data set presented here. A comparison between this data set and predictions in the references above are therefore not possible. It should be mentioned that the line fluxes calculated by the authors above are mainly for a wind scenario. In light of the results presented here concerning the Pa Beta and Br Gamma line profiles, such an approach must be taken with caution. A different approach in this regard was taken by Martin smartin1 and by Muzerolle, Calvet & Hartmann (1998). The former computes Br Gamma line fluxes in an accretion scenario assuming optically thin emission. Martin concludes that although the line luminosities are comparable to the ones observed, the expected line profiles differ substantially from those presented in Najita, Carr & Tokunaga (1996). This is confirmed by the much larger number of Br Gamma profiles presented here (when compared to the Najita et al. work). Muzerolle et al. compute Pa Beta and Br Gamma line fluxes for a magnetospheric accretion scenario. Their results on line fluxes still need to be observationally tested. Recall again that flux calibration of the data presented here was not done. Therefore, only the comparison of observed and model line profiles and line intensities relative to the continuum can be made.