Results 31 to 40 of about 20,346,263 (306)

H II regions with He II emission [PDF]

Publications of the Astronomical Society of the Pacific, 1991
H II regions which exhibit surprisingly strong nebular He II λ4686 emission, with I(λ4686)/I (Hβ) as high as 0.3 in some cases. The He II emission in-these objects is associated with a rather diverse set of stars, with WO stars, very early WN stars, and luminous X-ray binaries involved, and in one case what appears to be a normal O-type star. Extension
Donald R. Garnett, Robert C., Jr. Kennicutt, You-Hua Chu, Evan D. Skillman   +3 more
openaire   +1 more source

STATISTICS AND PROPERTIES OF H-II REGIONS IN NGC-6814

, 1993
We present a new Halpha image of high quality of the grand-design galaxy NGC 6814, and describe statistical properties of the H II region population. We have determined positions, angular sizes, and calibrated fluxes of 735 individual H II regions.
BECKMAN, JE, CEPA, J, KNAPEN, JH, ARNTHJENSEN, N   +3 more
core   +2 more sources

The Chocolate Chip Cookie Model: Dust-to-metal Ratio of H ii Regions

The Astrophysical Journal Letters, 2023
Using a sample of face-on star-forming galaxies selected from the Sloan Digital Sky Survey, we statistically derive the typical optical depth τ _cl of individual H ii regions based on the “Chocolate Chip Cookie” model of Lu et al. (2022).
Jiafeng Lu, Shiyin Shen, Fang-Ting Yuan, Qi Zeng   +3 more
doaj   +1 more source

Interstellar Bubbles in Two Young H II Regions [PDF]

, 2001
peer reviewedMassive stars are expected to produce wind-blown bubbles in the interstellar medium; however, ring nebulae, suggesting the existence of bubbles, are rarely seen around main-sequence O stars.
Nazé, Yaël, Rosado, Margarita, Points, Sean D, Chen, C-H Rosie, Danforth, Charles W, Chu, You-Hua   +5 more
core   +1 more source

Stellar associations powering H II regions

Astronomy & Astrophysics
Newly formed stars profoundly affect their environment by depositing energy and momentum into the surrounding gas. However, only a fraction of the stellar feedback is retained in the cloud, and observational constraints are needed to improve our ...
Scheuermann Fabian, Kreckel Kathryn, Teh Jia Wei, Belfiore Francesco, Groves Brent, Barnes Ashley T., Boquien Médéric, Chevance Mélanie, Dale Daniel A., Egorov Oleg, Glover Simon C. O., Grasha Kathryn, Hannon Stephen, Klessen Ralf S., Larson Kirsten L., Lee Janice C., Liang Fu-Heng, Lopez Laura A., Eduardo Méndez-Delgado J., Neumann Justus, Ostriker Eve, Pan Hsi-An, Ramambason Lise, Santoro Francesco, Schinnerer Eva, Thilker David A., Chris Tian Qiushi, Úbeda Leonardo, Whitmore Bradley C., Williams Thomas G.   +29 more
doaj   +1 more source

On the observed infrared fluxes from extragalactic H II regions

, 1977
We have calculated for extragalactic HII regions, the expected relationship between the radio flux at 11 cm and the infrared flux at 11 and 20 μm based on the grain models and the parameters which fit the observations of galactic H II regions.
Krishna Swamy, K. S., Iyengar, K. V. K.
core   +1 more source

ATLASGAL - properties of compact H II regions and their natal clumps [PDF]

, 2013
We present a complete sample of molecular clumps containing compact and ultracompact H?ii (UC H?ii) regions between ? = 10° and 60° and |b| < 1°, identified by combining the APEX Telescope Large Area Survey of the Galaxy submm and CORNISH radio continuum
Thompson, M. A., Thompson, M.A., Hoare, M., Lumsden, S. L., Urquhart, J., Purcell, C.R., Bronfman, L., Walmsley, C. M., Moore, T., Eden, D., Lumsden, S.L., Morgan, L. K., Urquhart, J. S., Bronfman Aguiló, Leonardo, Thompson, M., Moore, T. J. T., Moore, T.J.T., Hoare, M.G., Menten, K.M., Hoare, M. G., Kurtz, S., Eden, D.J., Eden, D. J., Morgan, L., Purcell, C. R., Walmsley, C.M., Urquhart, J.S., Menten, K. M., Morgan, L.K., Csengeri, T., Wyrowski, F., Menten, K., Schuller, F., Russeil, D., Morgan, LK, Moore, TJT, Purcell, CR, Hoare, MG, Walmsley, CM, Schuller, F, Kurtz, S, Bronfman, L, Thompson, MA, Eden, DJ, Lumsden, SL, Csengeri, T, Menten, KM, Wyrowski, F, Urquhart, JS, Russeil, D   +49 more
core   +1 more source

Integral field spectroscopy of a sample of nearby galaxies. II. Properties of the H II regions [PDF]

, 2012
This is an electronic version of an article published in Astronomy and Astrophysics. Sánchez, S.F. et al. Integral field spectroscopy of a sample of nearby galaxies. II. Properties of the H II regions.
D. Mast, Sánchez, S. F, Sánchez, S. F., Kehrig, C., R. C. Kennicutt, R. Cid Fernandes, Vílchez, J.M., Díaz Beltrán, Ángeles Isabel, Monreal Ibero, A., González Delgado, R., F. F. Rosales-Ortega, R. García-Benito, S. Ellis, Cid Fernandes, R., García Benito, Rubén, Ellis, S., A. Monreal-Ibero, Gil de Paz, A., Á. R. López-Sánchez, B. Husemann, Rosales Ortega, F. Fabián, Marino, R. A., Kennicutt, R. C., C. J. Walcher, A. Gil de Paz, Rosales Ortega, F. F., Mast, D., Marino, Raffaella Anna, Husemann, B., Iglesias Páramo, J., J. M. Vílchez, Gil De Paz, Armando, J. Bland-Hawthorn, R. A. Marino, Walcher, C. J., J. Iglesias-Páramo, A. I. Díaz, E. Pérez, Pérez, E., Walcher, C.J., López Sánchez, Á. R., S. F. Sánchez, R. González Delgado, Díaz, A. I., C. Kehrig, Vílchez, J. M., Bland Hawthorn, J., García Benito, R., López Sánchez, Á.R., García-Benito, Rubén, López-Sánchez, A.R., González-Delgado, R., Sánchez, Sebastián F., Mast, Damián, Rosales-Ortega, Fabián, Bland-Hawthorn, J., Vílchez Medina, José Manuel, Marino, R.A., Monreal-Ibero, Ana, Iglesias-Páramo, J.   +59 more
core   +1 more source

The Expansion of H II Regions

The Astrophysical Journal, 1968
H II regions expansion around O, B and A stars due to interstellar hydrogen ionization by stellar radiation ...
R. C. Newman, W. I. Axford
openaire   +1 more source

Electron Densities in H ii Regions from Observation of [N ii] 205 μm Fine Structure and Radio Recombination Lines

The Astrophysical Journal
We employ observations of the 205 μ m [N ii ] fine structure (FS) line and radio recombination line (RRL) emission to derive the electron density in 10 well-known H ii regions. The combination of these two spectral lines (the RRL–FS line method) provides
Paul. F. Goldsmith, L. D. Anderson, Jorge L. Pineda, Rebeca Aladro, Oliver Ricken   +4 more
doaj   +1 more source