Formaldehyde Absorption at [ITAL]z[/ITAL] = 0.685 toward the “Einstein Ring” B0218+357
Open Access
- 10 July 1996
- journal article
- research article
- Published by American Astronomical Society in The Astrophysical Journal
- Vol. 465 (2) , L99-L102
- https://doi.org/10.1086/310147
Abstract
We report VLA observations of absorption in the 211 → 212 transition of formaldehyde (H2CO) at a redshift of 0.68466 toward the Einstein ring gravitational lens system B0218+357. We observe the H2CO line at 8.6 GHz only toward the stronger of the two compact images of this system. The column densities of H2CO and other molecules previously observed at millimeter wavelengths, as well as their relative abundances, are comparable to the values one finds for molecular clouds within the Milky Way. We argue that the material seen in absorption has a molecular hydrogen column density between 5 × 1021 and 5 × 1022 cm-2.Keywords
This publication has 13 references indexed in Scilit:
- MG2016+112: A Double Gravitational Lens ModelPublished by Springer Nature ,1996
- The optical appearance of the gravitational lens system B0218+35.7Monthly Notices of the Royal Astronomical Society, 1995
- Formaldehyde as a probe of physical conditions in dense molecular cloudsThe Astrophysical Journal Supplement Series, 1993
- Neutral hydrogen 21 centimeter absorption at Z = 0.6847 toward the 'smallest Einstein ring'The Astrophysical Journal, 1993
- B0218 + 35.7: a gravitationally lensed system with the smallest separationMonthly Notices of the Royal Astronomical Society, 1993
- Radio and optical observations of 0218+357 - The smallest Einstein ring?The Astronomical Journal, 1992
- Distribution of CO in the Milky WayAnnual Review of Astronomy and Astrophysics, 1991
- Formaldehyde in envelopes of interstellar dark cloudsThe Astrophysical Journal, 1991
- The relationship between infrared, optical, and ultraviolet extinctionThe Astrophysical Journal, 1989
- A survey for dense cores in dark cloudsThe Astrophysical Journal Supplement Series, 1989