Radio recombination lines in Galactic H II regions

被引:71
作者
Quireza, Cintia
Rood, Robert T.
Balser, Dana S.
Bania, T. M.
机构
[1] Observ Nacl, BR-20921400 Rio De Janeiro, Brazil
[2] Univ Sao Paulo, Inst Astron Geofis & Ciencias Atmosfer, BR-05508900 Sao Paulo, Brazil
[3] Univ Virginia, Dept Astron, Charlottesville, VA 22903 USA
[4] Natl Radio Astron Observ, Green Bank, WV 24944 USA
[5] Boston Univ, Inst Astrophys Res, Boston, MA 02215 USA
关键词
HII regions; ISM : abundances; ISM : atoms; ISM : clouds; ISM : evolution; ISM : lines and bands; ISM : structure; nuclear reactions; nucleosynthesis; abundances; radio lines : ISM;
D O I
10.1086/503901
中图分类号
P1 [天文学];
学科分类号
0704 ;
摘要
We report radio recombination line (RRL) and continuum observations of a sample of 106 Galactic H II regions made with the NRAO 140 Foot (43 m) radio telescope in Green Bank, West Virginia. We believe this to be the most sensitive RRL survey ever made for a sample this large. Most of our source integration times range between 6 and 90 hr, yielding typical rms noise levels of similar to 1.0-3.5 mK. Our data result from two different experiments performed, calibrated, and analyzed in similar ways. A C II survey was made at the 3.5 cm wavelength to obtain accurate measurements of carbon radio recombination lines. When combined with atomic (C I) and molecular (CO) data, these measurements will constrain the composition, structure, kinematics, and physical properties of the photodissociation regions that lie on the edges of H II regions. A second survey was made at the 3.5 cm wavelength to determine the abundance of He-3 in the interstellar medium of the Milky Way. Together with measurements of the He-3(+) hyperfine line, we get high-precision RRL parameters for H, He-4, and C. Here we discuss significant improvements in these data with both longer integrations and newly observed sources.
引用
收藏
页码:338 / 359
页数:22
相关论文
共 38 条
[1]   The production of HI in photodissociation regions and a comparison with CO (1-0) emission [J].
Allen, RJ ;
Heaton, HI ;
Kaufman, MJ .
ASTROPHYSICAL JOURNAL, 2004, 608 (01) :314-322
[2]  
Altenhoff W. J., 1979, Astronomy and Astrophysics Supplement Series, V35, P23
[3]   THE COSMIC ABUNDANCE OF HE-3 .3. IMPROVED LINE PARAMETERS FOR SELECTED SOURCES [J].
BALSER, DS ;
BANIA, TM ;
BROCKWAY, CJ ;
ROOD, RT ;
WILSON, TL .
ASTROPHYSICAL JOURNAL, 1994, 430 (02) :667-681
[4]   The He-3 abundance in planetary nebulae [J].
Balser, DS ;
Bania, TM ;
Rood, RT ;
Wilson, TL .
ASTROPHYSICAL JOURNAL, 1997, 483 (01) :320-334
[5]   He-3 in the Milky Way interstellar medium: Summary of relevant observations [J].
Bania, TM ;
Balser, DS ;
Rood, RT ;
Wilson, TL ;
Wilson, TJ .
ASTROPHYSICAL JOURNAL SUPPLEMENT SERIES, 1997, 113 (02) :353-366
[6]   MEASUREMENTS OF THE HE-3 ABUNDANCE IN THE INTERSTELLAR-MEDIUM [J].
BANIA, TM ;
ROOD, RT ;
WILSON, TL .
ASTROPHYSICAL JOURNAL, 1987, 323 (01) :30-43
[7]   The cosmological density of baryons from observations of 3He+ in the Milky Way [J].
Bania, TM ;
Rood, RT ;
Balser, DS .
NATURE, 2002, 415 (6867) :54-57
[8]   DETAILED STRUCTURE OF CO IN MOLECULAR CLOUD COMPLEXES .2. W75-DR 21 REGION [J].
DICKEL, JR ;
DICKEL, HR ;
WILSON, WJ .
ASTROPHYSICAL JOURNAL, 1978, 223 (03) :840-853
[9]   H I IN THE GALAXY [J].
DICKEY, JM ;
LOCKMAN, FJ .
ANNUAL REVIEW OF ASTRONOMY AND ASTROPHYSICS, 1990, 28 :215-261
[10]  
FURST E, 1990, ASTRON ASTROPHYS SUP, V85, P691