Relation between CO and gamma-ray observations, cosmic rays, and the thickness of the galactic disk

Journal Article · Wed Oct 01 04:00:00 EDT 1975 · Astrophys. J., Lett., v. 201, no. 1, pp. L5-L8

DOI:https://doi.org/10.1086/181928· OSTI ID:4113501

Wentzel, D G; Jackson, P D; Rose, W K; Sinha, R P

Recent CO observations suggest that dense clouds provide a high mean gas density (mostly H$sub 2$ at approximately 5 kpc from the galactic center. Gamma- ray observations have been explained as resulting primarily from the interaction of cosmic rays with interstellar matter. The relationship between cosmic-ray density and mean gas density is discussed, and it is argued that the CO clouds must be dynamically independent of the gas that is observed in 21-cm line- radiation. A plausible upper limit to the cosmic-ray density at R=5 kpc is derived that is based on measurements of galactic disk thickness, hydrogen turbulent velocities from 21-cm line data, and an estimate of the ''distributed'' gas density which confines the cosmic rays to the disk. This upper limit is approximately 5 times the cosmic-ray density near the Sun. Observations of the thickness of the galactic disk suggest that the cosmic-ray density increases with distributed gas density. (AIP)

• Research Organization: Univ. of Maryland, College Park
• Sponsoring Organization: USDOE
• NSA Number: NSA-33-017950
• OSTI ID: 4113501
• Journal Information: Astrophys. J., Lett., v. 201, no. 1, pp. L5-L8, Journal Name: Astrophys. J., Lett., v. 201, no. 1, pp. L5-L8; ISSN AJLEA
• Country of Publication: United States
• Language: English

Related Subjects

*COSMIC GASES-- FLUX DENSITY
*COSMIC RAY FLUX-- FLUX DENSITY
*INTERSTELLAR SPACE-- GAMMA RADIATION
640101* --Physics Research--Astrophysics & Cosmology--Cosmic Radiation
CARBON MONOXIDE
DENSITY
MASS
MILKY WAY
N56100* --Physics (Astrophysics & Cosmology)--Cosmic Radiation
N56500 --Physics (Astrophysics & Cosmology)--Galaxies