The Diffuse Interstellar Bands

The mystery of the diffuse interstellar bands has been variously a curiosity, a co nundrum, and a nuisance for astronomers in the seven decades since the features were first noticed, but recently they have become a forefront issue in astrophysics. Ever since Paul Merrill, in a series of papers starting in 1934, pointed out the interstellar and unidentified nature of the bands, a Who's Who of twentieth century astronomers have tried their hands at solving the problem of identifying the carriers. Henry Norris Russell, Pol Swings, Otto Struve, Paul Ledoux, W. W. Morgan, Walter Adams, Jesse Greenstein, Lawrence Aller, and Gerhard Herzberg all briefly entered the stage, only to move on quickly to other problems where the chances for progress appeared more realistic. In more recent times a number of equally prominent scientists have pursued the bands, but generally only as a sideline to their real astronomical research. But in the past decade, and particularly in the past three years, the view of the search for the diffuse band absorbers as an interesting but perhaps quixotic quest has changed. Today there are several astronomers, as well as laboratory chemists, who are devoting substantial research time and resources to the problem and, as perhaps the most reliable indicator of the newly elevated status of research in this field, some research grants have now been awarded for the study of the bands.

Inhalt
Contenst.- I: Observational Characteristics of the Diffuse Bands.- The Diffuse Bands: A Review with Speculations.- Diffuse Interstellar Bands in Individual Sightlines.- Ultra-High-Resolution Spectroscopy of Diffuse Bands.- The Diffuse Interstellar Bands Towards Southern Stars.- The Diffuse Interstellar Band Spectrum.- Revisiting Diffuse Interstellar Bands in the Satellite Ultraviolet with the Goddard High Resolution Spectrograph.- Diffuse Interstellar Bands in the Near Infrared A Dedicated Search for Polycyclic Aromatic Hydrocarbon and Fullerene Cations.- A Search for Polarization in Diffuse Interstellar Bands Towards HD197770.- II: Environmental Behavior of the Diffuse Interstellar Bands.- Collective Behaviour of the Diffuse Interstellar Bands.- DIBS and UV Extinction.- The Environment Dependence of Diffuse Interstellar Bands.- Diffuse Interstellar Bands in the Young Galactic Clusters M16 and M17.- The Interstellar Space Mosaic: A User Interface for Accessing ISM Data World-Wide Distributed.- Diffuse Circumstellar Bands.- Red Rectangle Emission Bands.- HAC and the ERE.- Visible Luminescence From PAH Cations and the Diffuse Bands in Emission.- Carrier of the Emission ?5797 DIB in the Red Rectangle: Suprathermally Rotating PAH?.- III: Laboratory Studies of Proposed Carriers.- Laboratory Studies of DIB Carriers.- Laboratory Studies of Highly Unsaturated Carbon Chains and the Diffuse Interstellar Bands.- Absorption Spectroscopy of Neutral and Ionized PAHs. Implications for the Diffuse Interstellar Bands.- A Critical Assessment of the PAH Hypothesis: Revisited.- Photofragmentation of Isolated PAH Cations.- Experimental Study of Naphthalene and Anthracene Reactions.- IV: Diffuse Bands and Interstellar Dust.- The Diffuse Interstellar Bands and Interstellar Dust.- DustGrain Carriers and the Diffuse Band Profiles.- Interstellar Polarization.- Polarization of the 2175 Å Feature.- V: Theoretical Studies of Molecular Carriers.- Spectroscopy and Photophysics of Possible Large Molecule Carriers of the Diffuse Interstellar Bands.- Large Molecules in the Interstellar Medium.- Charge Variation of Polycyclic Aromatic Hydrocarbons in the Diffuse Interstellar Medium.- VI: Proposed Carriers.- Observational Constraints on the Carriers of the Diffuse Bands.- Porphyrins Within Interstellar Grains.- Fulleranes and the Diffuse Interstellar Bands.- DIB Carriers on Grain Surfaces.- PAH Cations as Candidates to the DIB Carriers.- Carbon Chains and the Diffuse Interstellar Bands.- A Critique of Suggested Diffuse Band Carriers.- Summary.- Addresses of Participants.- Index of Specific Diffuse Bands.