Does tiny-scale atomic structure exist in the interstellar medium ?

Abstract

We report on preliminary results from the recent multi-epoch neutral hydrogen absorption measurements toward three pulsars, B0823+26, B1133+16 and B2016+28, using the Arecibo telescope. We do not find significant variations in optical depth profiles over periods of 0.3 and 9--10 yr, or on spatial scales of 10--20 and 70--85 AU. The large number of non detections of the tiny scale atomic structure suggests that the AU-sized structure is not ubiquitous in the interstellar medium and could be quite a rare phenomenon.

Accepted by ApJ Letters, 5 pages, 2 figures

References in corpus (8)

• The Millennium Arecibo 21-CM Absorption Line Survey. II. Properties of the Warm and Cold Neutral Media
• The Distribution of Thermal Pressures in the Interstellar Medium from a Survey of C I Fine-Structure Excitation
• The Small-scale Structure in Interstellar HI: A Resolvable Puzzle
• The Structure of the Cold Neutral ISM on 10-100 Astronomical Unit Scales
• A Na I Absorption Map of the Small-Scale Structure in the Interstellar Gas Toward M15
• Multi-epoch HI line measurements of 4 southern pulsars
• Detection of OH absorption against PSR B1849+00
• Small-Scale Variations of HI Spectra from Interstellar Scintillatio

Cited by in corpus (21)

• Families of Plausible Solutions to the Puzzle of Boyajian's Star
• Drastic changes in the molecular absorption at redshift z=0.89 toward the quasar PKS 1830-211
• Atomic and Ionized Microstructures in the Diffuse Interstellar Medium
• Spatial and Temporal Variations in Small-Scale Galactic HI Structure Toward 3C~138
• Tiny HI Clouds in the Local ISM
• Arecibo HI Absorption Measurements of Pulsars and the Electron Density at Intermediate Longitudes in the First Galactic Quadrant
• Small-scale structure in the interstellar medium: time-varying interstellar absorption towards κ Velorum
• Monitoring the Variable Interstellar Absorption toward HD 219188 with HST/STIS
• Arecibo Multi-Epoch HI Absorption Measurements Against Pulsars: Tiny-Scale Atomic Structure
• Tiny scale opacity fluctuations from VLBA, MERLIN and VLA observations of HI absorption toward 3C 138
• Spatial Variations in Galactic H I Structure on AU-Scales Toward 3C 147 Observed with the Very Long Baseline Array
• Spatial and Temporal Variations in Interstellar Absorption toward HD 72127AB
• MHD Stability of ISM Phase Transition Layers I: Magnetic Field Orthogonal to Front
• The Complex Interstellar Na I Absorption toward h and Chi Persei
• Distance of PSR B0458+46 indicated by FAST HI absorption observations
• Limits on Turbulent HI Fluctuations Towards PSR B0329+54 On Scales Between 0.0025 and 12.5 AU
• Tiny HI Clouds in the Local ISM
• Galactic HI on the 50-AU scale in the direction of three extra-galactic sources observed with MERLIN
• Apparent Faster-Than-Light Pulse Propagation in Interstellar Space: A new probe of the Interstellar Medium
• The EDIBLES survey VI. Searching for time variations of interstellar absorption features
• H I absorption line and anomalous dispersion in the radio pulses of PSR B1937+21