A high resolution study of near-IR diffuse interstellar bands, search for small scale structure, time variability and stellar features

Abstract

Diffuse interstellar bands comprise hundreds of absorption features in the ISM. Most DIBs are observed in the optical, but some are in the IR. We observed 76 early-type stars at R=50,000 and S/N ratios of several hundreds using CRIRES. We measure DIBs around 1318, 1527, 1561, 1565, 1567, 1574 and/or 1624 nm. We detect a total of 6 DIB features and 17 likely stellar features assisted by a CMFGEN model. We also measured the DIBs at 1318 and 1527 nm using X-shooter towards ten Ceph. variables with 3.2 < E(B-V) < 6.5 and 4 stars at low values of water vapour. Correlation coeffs. of 0.73-0.96 are found comparing NIRDIB eq. width vs. E(B-V) and with r > 0.8 when comparing the NIR and optical DIBs 5705, 5780, 6203, 6283 and 6269 A. The 5797 A DIB is less well correlated with the NIDIBs. The "C60+" DIB at 9632 A is not well correlated with the 1318 nm DIB. Partial correlation coefficients using E(B-V) as the covariate were also determined. For stars earlier than B2, the 1318 nm DIB is affected by an emission line on its blue wing, likely stellar in nature, although we cannot rule out interstellar/circumstellar origin for example caused by by a DIB in emission. The 1318 nm DIB has a red wing and is reasonably well fitted by two gaussians. Neither the component ratios nor separation are correlated with 5780/5797 or E(B-V). EW(1318 nm) correlates with HI with EW(1318 nm)/E(B-V) decreasing with f(H2). Five pairs of stars within 1 am show similar 1318 nm DIB profiles. Variation in 1318 nm is seen in HD 145501/145502 and HD 168607/168625 pairs. CRIRES data for 17 stars separated by 6-14 months and 2 X-shooter sightlines separated by 9.9 yr were analysed. No time-variability is detected in the 5780, 5797 A, 1318 nm or 1527 nm DIBs. Tentative time variation is observed in the C60+ DIBs at 9577 and 9632 A towards HD 183143 although very close to the noise level with confirmation required.

Accepted for publicaion in the main journal of Astronomy and Astrophysics on 25th November 2022

References in corpus (27)

• Molecfit: A general tool for telluric absorption correction. I. Method and application to ESO instruments
• A Catalog of Diffuse Interstellar Bands in the Spectrum of HD 204827
• A census of the Wolf-Rayet content in Westerlund 1 from near-infrared imaging and spectroscopy
• Studies of the Diffuse Interstellar Bands. III. HD 183143
• A multi-wavelength view on the dusty Wolf-Rayet star WR 48a
• Evolutionary state of magnetic chemically peculiar stars
• VLT/UVES Observations of Interstellar Molecules and Diffuse Bands in the Magellanic Clouds
• Confirming interstellar C${}_{60}^{+}$ using the Hubble Space Telescope
• The X-shooter Spectral Library (XSL): I. DR1. Near-ultraviolet through optical spectra from the first year of the survey
• Age Determination in Upper Scorpius with Eclipsing Binaries
• Metallicity-dependent wind parameter predictions for OB stars
• VLT/X-shooter survey of near-infrared diffuse interstellar bands
• Mapping the Interstellar Medium with Near-Infrared Diffuse Interstellar Bands
• The ESO Diffuse Interstellar Bands Large Exploration Survey: EDIBLES I. Project description, survey sample and quality assessment
• Discovery of new magnetic early-B stars within the MiMeS HARPSpol survey
• C${}_{60}^{+}$ - looking for the bucky-ball in interstellar space
• Near-infrared diffuse interstellar bands in 0.91-1.32 micron
• Using classical Cepheids to study the far side of the Milky Way disk: I. Spectroscopic classification and the metallicity gradient
• The Behavior of Selected Diffuse Interstellar Bands with Molecular Fraction in Diffuse Atomic and Molecular Clouds
• Diffuse Interstellar Bands and the Ultraviolet Extinction Curves: The Missing Link Revisited
• Survey of near-infrared diffuse interstellar bands in $Y$ and $J$ bands. I. Newly identified bands
• Early-type stars observed in the ESO UVES Paranal Observatory Project - V. Time-variable interstellar absorption
• Abundance analysis of 5 early-type stars in the young open cluster IC2391
• Mapping diffuse interstellar bands in the local ISM on small scales via MUSE 3D spectroscopy
• Emission Lines in the Near-infrared Spectra of the Infrared Quintuplet Stars in the Galactic Center
• Probing the Local Bubble with Diffuse Interstellar Bands. III. The Northern hemisphere data and catalog
• TRES Survey of Variable Diffuse Interstellar Bands

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