VLT/X-shooter survey of near-infrared diffuse interstellar bands

Abstract

This paper presents a spectral survey of diffuse interstellar bands (DIBs) in the NIR range, from 0.9 to 2.5 micron. The observations were designed to detect new DIBs, confirm previously proposed NIR DIBs, and characterise their behaviour with respect to known line-of-sight properties (including the optical DIBs present in our spectra). X-shooter at the VLT was used to obtained medium-resolution spectra of eight known DIB targets and one telluric reference star. In addition to the known 9577, 9632, 10780, 11797, and 13175 Angstroms NIR DIBs, we confirm 9 out of the 13 NIR DIBs that were presented by Geballe and co-workers in 2011. Furthermore, we report 12 new NIR DIB candidates. The strengths of the strongest NIR DIBs show a general correlation with reddening, E(B-V), but with a large scatter. Several NIR DIBs are more strongly correlated with the 5780 Angstroms DIB strength than with E(B-V); this is especially the case for the 15268 Angstroms DIB. The NIR DIBs are strong: the summed equivalent widths of the five strongest NIR DIBs represent a few percent of the total equivalent width of the entire average DIB spectrum (per unit reddening). The NIR DIBs towards the translucent cloud HD 147889 are all weak with respect to the general trend. No direct match was found between observed NIR DIBs and laboratory matrix-isolation spectroscopic data of PAHs. The strong correlation between the 5780-15268 DIB pair implies that (Nf)_5780 / (Nf)_15268 = 14. However, the reduced strength of the 15268 Angstroms DIB in HD 147889 rules out a common carrier for these two DIBs. Since the ionisation fraction for small PAHs in this translucent cloud is known to be low compared to diffuse clouds, the weakness of the 15268 Angstrom DIB suggests that an ionised species could be the carrier of this NIR DIB. (abridged).

arXiv commentAccepted for publication in A&A. 13 pages. Revision

References in corpus (9)

• X-shooter, the new wide band intermediate resolution spectrograph at the ESO Very Large Telescope
• A Method of Correcting Near-Infrared Spectra for Telluric Absorption
• The Diffuse Interstellar Bands: A Major Problem in Astronomical Spectroscopy
• Studies of the Diffuse Interstellar Bands. III. HD 183143
• Studies of Diffuse Interstellar Bands. V. Pairwise Correlations of Eight Strong DIBs and Neutral Hydrogen, Molecular Hydrogen, and Color Excess
• Abundances of PAHs in the ISM: Confronting Observations with Experimental Results
• Infrared Diffuse Interstellar Bands in the Galactic Centre Region
• Spectral atlas of massive stars around He I 10830 A
• Dust properties along anomalous extinction sightlines. II. Studying extinction curves with dust models

Cited by in corpus (39)

• Interstellar Fullerene Compounds and Diffuse Interstellar Bands
• The Apache Point Observatory Catalog of Optical Diffuse Interstellar Bands
• Mapping the Interstellar Medium with Near-Infrared Diffuse Interstellar Bands
• Detection of Buckminsterfullerene emission in the diffuse interstellar medium
• C${}_{60}^{+}$ and the Diffuse Interstellar Bands: An Independent Laboratory Check
• Near-infrared diffuse interstellar bands in 0.91-1.32 micron
• EDIBLES II. On the detectability of C60+ bands
• Near infrared diffuse interstellar bands toward the Cygnus OB2 association
• Near-infrared diffuse interstellar bands in APOGEE telluric standard star spectra: weak bands and comparisons with optical counterparts
• Medium resolution near-infrared spectroscopy of Massive Young Stellar Objects
• Diffuse Interstellar Bands and the Ultraviolet Extinction Curves: The Missing Link Revisited
• A catalog of 1.5273 micron diffuse interstellar bands based on APOGEE hot telluric calibrators
• Stellar population astrophysics (SPA) with the TNG. GIANO-B spectroscopy of red supergiants in Alicante 7 and Alicante 10
• 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
• Kinetic Tomography. II. A second method for mapping the velocity field of the Milky Way Interstellar Medium and a comparison with spiral structure models
• VLT/MUSE discovers a jet from the evolved B[e] star MWC 137
• Intermediate-size fullerenes as degradation products of interstellar PAHs
• Survey of near-infrared diffuse interstellar bands in $Y$ and $J$ bands. I. Newly identified bands
• Diffuse interstellar bands λ5780 and λ5797 in the Antennae Galaxy as seen by MUSE
• Diffuse interstellar bands in the HII region M17: Insights into their relation with the total-to-selective visual extinction $R_V$
• M giants with IGRINS I. Stellar parameters and $\alpha$-abundance trends of the solar neighborhood population
• C${}_{60}^{+}$ diffuse interstellar band correlations and environmental variations
• An Infrared Diffuse Circumstellar Band? The Unusual 1.5272 Micron DIB In the Red Square Nebula
• The diffuse interstellar band around 8620 Å II. Kinematics and distance of the DIB carrier
• A high resolution study of near-IR diffuse interstellar bands, search for small scale structure, time variability and stellar features
• Optical and infrared study of the obscured B[e] supergiant high-mass X-ray binary IGR J16318-4848
• The 15273 Å diffuse interstellar band in the dark cloud Barnard 68
• First detection of $A$--$X$ (0,0) bands of interstellar C${}_2$ and CN
• Correlation between UV resilience and wavelength of narrow DIBs
• Laser-induced fragmentation of coronene cations
• Diffuse interstellar bands as dust indicators: the contribution from 3D maps
• Near-Infrared Diffuse Interstellar Bands towards Her 36
• Spectroscopic study of Herbig Ae/Be stars in the Galactic Anti-center region from LAMOST DR5
• The Pristine Inner Galaxy Survey (PIGS) VI: Different vertical distributions between two DIBs at 442.8 nm and 862.1 nm
• Measuring Diffuse Interstellar Bands with cool stars. An improved line list to model the background stellar spectra
• Survey of Profile Parameters of the $6196\mathring{A}$ Diffuse Interstellar Band. From Uniform Profiles to Doppler Splitting and Blueshifts
• Mapping the diffuse interstellar bands $\lambda$5780 and $\lambda$6284 in the luminous infrared galaxy merger NGC 6240
• Classification of 3 accreting binaries with VLT/X-Shooter spectra
• Families and Clusters of Diffuse Interstellar Bands: a Data-Driven Correlation Analysis