J/A+A/662/A81 CRIRES NIR-DIBs (Ebenbichler+, 2022) ================================================================================ CRIRES high-resolution near-infrared spectroscopy of diffuse interstellar band profiles. Detection of 12 new DIBs in the YJ band and the introduction of a combined ISM sight line and stellar analysis approach. Ebenbichler A., Postel A., Przybilla N., Seifahrt A., Wessmayer D., Kausch W., Firnstein M., Butler K., Kaufer A., Linnartz H. =2022A&A...662A..81E (SIMBAD/NED BibCode) ================================================================================ ADC_Keywords: Interstellar medium ; Stars, supergiant ; Spectra, infrared Keywords: dust, extinction - ISM: lines and bands - ISM: molecules - line: profiles - stars: early-type - supergiants Abstract: A high spectral resolution investigation of diffuse interstellar bands (DIBs) in the near-infrared (YJ band) is conducted to test new methods, to confirm and improve existing parameters, and to search for new DIBs. Methods: The CRyogenic high-resolution InfraRed Echelle Spectrograph (CRIRES) on the European Southern Observatory's Very Large Telescope was employed to obtain spectra of four reddened background supergiant stars (HD 183143, HD 165784, HD 92207, HD 111613) and an unreddened comparison star (HD 87737) at the highest resolution of R~100000 currently achievable at near-infrared wavelengths. The correction for telluric absorption was performed by a modelling approach. Non-local thermodynamic equilibrium spectral modelling of available optical and the new near-infrared spectra facilitated a comprehensive characterisation of the atmospheric properties of the background stars. A more precise and accurate determination of the reddening law along the sight lines could be achieved than feasible before by comparison of the observed and model spectral energy distributions. For DIBs that overlap with stellar lines the DIB profile shapes could be recovered. Results: Seventeen known near-infrared DIBs were confirmed, and 12 previously unknown and generally weaker DIBs were identified in the YJ band. Three DIBs that show uniform profiles along all sight lines were identified, possibly connected to transitions from a common lower state of the same carrier. The divergent extinction curve towards the frequently discussed DIB standard star HD 183143 could be reproduced for the first time, requiring extra absorption by ~3.5 mag due to polycyclic aromatic hydrocarbons (PAHs) to match the ultraviolet extinction bump. This extra absorption probably stems from a circumstellar bubble lying in front of the star which is intersected tangentially by the line of sight. Description: The spectra were used for DIB measurements in the publication. They were obtained by oCRIRES at VLT during filler programmes. All spectra are in vacuum wavelengths in the barycentric restframe. Flux values are in arbitrary units for HD 183143 and HD 165784 and normalized for HD 111613 and HD 92207. Objects: -------------------------------------------------- RA (2000) DE Designation(s) -------------------------------------------------- 12 51 17.98 -60 19 47.2 HD 111613 = V* DS Cru 18 08 38.59 -21 26 58.4 HD 165784 = V* V4381 Sgr 19 27 26.56 +18 17 45.2 HD 183143 = V* HT Sge 10 37 27.07 -58 44 00.0 HD 92207 = V* V370 Car -------------------------------------------------- File Summary: -------------------------------------------------------------------------------- FileName Lrecl Records Explanations -------------------------------------------------------------------------------- ReadMe 80 . This file tablea1.dat 61 80 *Characterisation of the detected DIBs and new DIB candidates list.dat 86 70 List of spectra sp/* . 70 Individual spectra -------------------------------------------------------------------------------- Note on tablea1.dat: Non-detection of DIBs are a result either of a strength too low for detection or of missing spectral coverage. -------------------------------------------------------------------------------- Byte-by-byte Description of file: tablea1.dat -------------------------------------------------------------------------------- Bytes Format Units Label Explanations -------------------------------------------------------------------------------- 1- 9 A9 --- Star Star name 11- 15 I5 --- DIB DIB name 16- 18 A3 --- n_DIB Note on DIB (1) 20 I1 --- r_DIB Reference for DIB (2) 22- 28 F7.1 0.1nm lambda0air Rest wavelength, {lambda}_0,air_, in the barycentric rest frame (3) 30- 32 F3.1 0.1nm e_lambda0air rms uncertainty on lambda0air 34- 40 F7.1 0.1nm lambdavac Central wavelength in vacuum, {lambda}_vac_, in the barycentric rest frame 42- 44 I3 0.1pm EW Equivalent width 46- 47 I2 0.1pm e_EW rms uncertainty on EW 49- 52 F4.1 % Ac Central depth 54- 57 F4.1 % e_Ac rms uncertainty on Ac 59- 61 F3.1 0.1nm FWHM Full width at half maximum -------------------------------------------------------------------------------- Note (1): Notes for stellar blends as follows: a = MgII, {lambda}_air_ = 9631.891, 9632.430{AA} b = FeII, {lambda}_air_ = 10501.504{AA} c = NI, {lambda}_air_ = 10506.997{AA} d = HeI, {lambda}_air_ = 11044.983{AA} e = CI, {lambda}_air_ = 11801.098{AA} f = HeI, {lambda}_air_ = 11969.060, 11969.464{AA} Note (2): Referencas as follows: 1 = Joblin et al. (1990Natur.346..729J) 2 = Foing & Ehrenfreund (1994Natur.369..296F) 3 = Groh et al. (2007A&A...465..993G, Cat. J/A+A/465/993) 4 = Cox et al. (2014A&A...569A.117C) 5 = Hamano et al. (2015ApJ...800..137H) 6 = This work Note (3): Rest wavelengths have a systematic error of +/-0.3{AA} due to the double KI components (see Section 5). -------------------------------------------------------------------------------- Byte-by-byte Description of file: list.dat -------------------------------------------------------------------------------- Bytes Format Units Label Explanations -------------------------------------------------------------------------------- 1- 62 A62 --- Title Title of the spectrum file 64- 86 A23 --- FileName Name of the spectrum file in subdirectory sp -------------------------------------------------------------------------------- Byte-by-byte Description of file: sp/* -------------------------------------------------------------------------------- Bytes Format Units Label Explanations -------------------------------------------------------------------------------- 1- 10 F10.4 0.1nm lambda Barycentric wavelength in vacuum 12- 25 F14.5 --- Flux Flux (1) -------------------------------------------------------------------------------- Note (1): Flux values are in arbitrary units for HD 183143 and HD 165784 and normalized for HD 111613 and HD 92207. -------------------------------------------------------------------------------- Acknowledgements: Alexander Ebenbichler, alexander.ebenbichler(at)uibk.ac.at ================================================================================ (End) Alexander Ebenbichler [Univ. Innsbruck], P. Vannier [CDS] 06-May-2022