Diffuse interstellar bands in RAVE survey spectra

We have used spectra of hot stars from the RAVE Survey in order to investigate the visibility and properties of five diffuse interstellar bands previously reported in the literature. The RAVE spectroscopic survey for Galactic structure and kinematics records CCD spectra covering the 8400–8800 A wavelength region at 7500 resolving power. The spectra are obtained with the UK Schmidt at the AAO, equipped with the 6dF multi-fiber positioner. The DIB at 8620.4 A is by far the strongest and cleanest of all DIBs occurring within the RAVE wavelength range, with no interference by underlying absorption stellar lines in hot stars. It correlates so tightly with reddening that it turns out to be a reliable tool to measure it, following the relation EB−V = 2.72(±0.03) × EW (A), valid throughout the general interstellar medium of our Galaxy. The presence of a DIB at 8648 A is confirmed. Its intensity appears unrelated to reddening, in agreement with scanty and preliminary reports available in the literature, and its measurability is strongly compromised by severe blending with underlying stellar He I doublet at 8649 A. The two weak DIBs at 8531 and 8572 A do not appear real and should actually be blends of underlying stellar lines. The very weak DIB at 8439 A cannot be resolved within the profile of the much stronger underlying hydrogen Paschen 18 stellar line.

[1]  B. Gibson,et al.  THE RADIAL VELOCITY EXPERIMENT (RAVE): SECOND DATA RELEASE , 2008, 0806.0546.

[2]  L. Holmlid.  The diffuse interstellar band carriers in interstellar space: all intense bands calculated from He doubly excited states embedded in Rydberg Matter , 2008 .

[3]  F. Bresolin,et al.  Detection of diffuse interstellar bands in M 31 , 2008, 0801.3609.

[4]  B. Gibson,et al.  Galactic kinematics with RAVE data - I. The distribution of stars towards the Galactic poles , 2008, 0801.2120.

[5]  B. Gibson,et al.  Is the sky falling? Searching for stellar streams in the local Milky Way disc in the CORAVEL and RAVE surveys , 2007, 0709.4219.

[6]  K. Sandstrom,et al.  A Preliminary Investigation of the Diffuse Interstellar Line at 8621 Å , 2007 .

[7]  Arfon M. Smith,et al.  Diffuse interstellar bands in z < 0.6 Ca ii absorbers★ , 2007, 0710.0901.

[8]  B. Foing,et al.  Interstellar gas, dust and diffuse bands in the SMC , 2007 .

[9]  S. Iglesias-Groth.  Fullerenes and the 4430 Å Diffuse Interstellar Band , 2007 .

[10]  Bernard H. Foing,et al.  Linear and circular polarisation of diffuse interstellar bands , 2007 .

[11]  P. Gnaciński,et al.  Electron density and carriers of the diffuse interstellar bands , 2007, astro-ph/0701037.

[12]  B. Gibson,et al.  The RAVE Survey: Constraining the Local Galactic Escape Speed , 2006, Proceedings of the International Astronomical Union.

[13]  Olivier Bienayme,et al.  THE RADIAL VELOCITY EXPERIMENT (RAVE): FIFTH DATA RELEASE , 2013, 1609.03210.

[14]  B. Foing,et al.  The Large Magellanic Cloud: diffuse interstellar bands, atomic lines and the local environmental conditions , 2006 .

[15]  Farid Salama,et al.  Investigation of the Ultraviolet, Visible, and Near-Infrared Absorption Spectra of Hydrogenated Polycyclic Aromatic Hydrocarbons and Their Cations , 2005 .

[16]  J. Sollerman,et al.  Diffuse Interstellar Bands in NGC 1448 , 2004, astro-ph/0409340.

[17]  E. Burbidge,et al.  Dust and Diffuse Interstellar Bands in the za = 0.524 Absorption System toward AO 0235+164 , 2004, astro-ph/0407281.

[18]  B. Foing,et al.  Spectroscopy of large PAHs Laboratory studies and comparison to the Diffuse Interstellar Bands , 2002 .

[19]  J. Black,et al.  Interstellar C$_\mathsf{2}$ and CN toward the Cyg OB2 association - A case study of X-ray induced chemistry , 2001 .

[20]  U. Munari,et al.  High resolution spectroscopy over 8500-8750 Åfor GAIA - III. A library of synthetic spectra for 7750$\leq$ ${\vec {T}}_{\mathsf {eff}}\leq$ 50 000 K , 2001 .

[21]  J. Krełowski,et al.  Origin of diffuse interstellar bands: spectroscopic studies of their possible carriers , 2000 .

[22]  Michael S. Bessell,et al.  The Hipparcos and Tycho Photometric System Passbands , 2000 .

[23]  G. Walker,et al.  Narrow Diffuse Interstellar Bands: A Survey with Precise Wavelengths , 2000 .

[24]  T. Heckman,et al.  The Detection of the Diffuse Interstellar Bands in Dusty Starburst Galaxies , 2000, astro-ph/0002399.

[25]  S. Saito.  Sulfur-bearing Carbon-chain Molecules in Space and in the Laboratory , 1999 .

[26]  S. Leach.  Laboratory studies of polycyclic aromatic hydrocarbons, fullerenes and linear carbon chains in an astrophysical context , 1995 .

[27]  S. M. Scarrott,et al.  Molecular Diffuse Interstellar Band Carriers in the Red Rectangle , 1995, Science.

[28]  George H. Herbig,et al.  The Diffuse Interstellar Bands , 1995 .

[29]  G. Herbig,et al.  The Diffuse Interstellar Bands. VIII. New Features between 6000 and 8650 Angstrom , 1991 .

[30]  R. Snell,et al.  New diffuse interstellar bands in the wavelength region 6500-8900 A , 1978 .

[31]  Nancy Houk,et al.  Michigan catalogue of two-dimensional spectral types for the HD stars , 1975 .

[32]  P. Swings,et al.  Considerations Regarding Interstellar Molecules , 1937 .

[33]  P. Merrill.  No. 536. Stationary lines in the spectrum of the binary star Boss 6142. , 1936 .

[34]  P. Merrill.  UNIDENTIFIED INTERSTELLAR LINES , 1934 .