- ID:
- ivo://CDS.VizieR/J/A+A/428/837
- Title:
- HII regions in minor mergers of galaxies
- Short Name:
- J/A+A/428/837
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the results of the B, V and I photometry of eleven southern minor mergers. The total apparent B magnitude, integrated B-V and V-I colours were measured. We built B, V, and I equivalent profiles for each galaxy and decomposed them into bulge and disk components when possible. From H{alpha}+N[II] images we have estimated the basic photometric parameters of the HII regions, such as position, size, B-V and V-I colours, H{alpha}+[NII] luminosity and EW(H{alpha}+[NII]) equivalent width.
Number of results to display per page
Search Results
- ID:
- ivo://CDS.VizieR/J/ApJS/105/93
- Title:
- H II Regions in Nearby Seyfert Galaxies
- Short Name:
- J/ApJS/105/93
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Continuum-subtracted Halpha images of 17 nearby Seyfert galaxies are presented. The images are calibrated astrometrically using the Hubble Space Telescope Guide Star Catalog reference frame. For each galaxy, an inventory of H II regions detected using the COSMOS image classifier and centroider is provided. Salient features of each galaxy are described, including the distribution of the H II regions with reference to the galaxy morphology. Relevant abundance data from the literature are noted for each object. These images will find use as finding charts for follow-up spectrophotometric investigations of abundances, abundance gradients, and kinematics of H II regions in active galaxies, and for detailed studies of H II region populations in these objects.
- ID:
- ivo://CDS.VizieR/J/A+A/466/905
- Title:
- HII regions in NGC 628
- Short Name:
- J/A+A/466/905
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Properties of HII region populations in spiral galaxies provide important information about the physics of star formation as well as regional turbulent motions in the interstellar medium. We present a set of 376 photometrically calibrated HII regions in the nearby late-type spiral galaxy NGC 628. We have studies the mean velocity and velocity dispersion for the H-alpha-emitting gas in NGC 628 and found with widely distributed star formation in the disc plane. The H-alpha emission from the HII regions dominates any emission from the diffuse component in this galaxy.
- ID:
- ivo://CDS.VizieR/J/other/Ap/50.426
- Title:
- HII regions in NGC 6384
- Short Name:
- J/other/Ap/50.42
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The galaxy NGC6384 has been observed with an IPCS through H{alpha} and [NII] narrow-band interference filters for direct imagery with the 2.6-m Byurakan telescope. We studied the main physical parameters of the identified 98 HII regions, their diameter and luminosity functions, as well the [NII]/H{alpha} ratio distribution.
- ID:
- ivo://CDS.VizieR/J/A+A/545/A43
- Title:
- HII regions in NGC 628 and NGC 6946
- Short Name:
- J/A+A/545/A43
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present here two HII region catalogues with azimuthal resolution for the two grand design galaxies NGC 628 and NGC 6946. With the help of these catalogues, we study several properties of the star-forming processes occurring in spiral galaxies. We obtained direct imaging in the narrow-band filters centred at H{alpha}, H{beta}, [OII]{lambda}3727, and [OIII]{lambda}{lambda}4959, 5007 and their respective continua. After the calibration and correction of the data, we obtained for each HII region the de-reddened fluxes in the aforementioned lines, the size, the H{alpha} equivalent width, and, using two different empirical calibrations, the metallicity. Employing a method based on the Delaunay triangulation, a two-dimensional (2D) representation of the metallicity was obtained.
- ID:
- ivo://CDS.VizieR/J/PASP/123/649
- Title:
- HII regions in OB associations
- Short Name:
- J/PASP/123/649
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Using the data from the NOAO Local Group Survey, we have measured the H{alpha} fluxes of 291 nebulae associated with 21 of the van den Bergh OB associations. We have combined these data together with six-color HST WFPC2 photometry, in order to identify the most UV-bright stars in the region. The simple purpose of this article is to explore the spatial relationships between these components.
- ID:
- ivo://CDS.VizieR/J/ApJS/101/287
- Title:
- H II Regions in Seyfert galaxies. I.
- Short Name:
- J/ApJS/101/287
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Data on positions, effective diameters, and absolute fluxes of H II regions on 21 Seyfert spiral galaxies are presented together with the H{alpha} + [N II] images and identification charts. The objects are selected from a larger emission-line survey of a distance-limited sample of southern Seyfert galaxies. Statistical analysis of the data as well as discussion and comparison of the H II region populations in Seyfert and normal galaxies will be presented in forthcoming papers.
- ID:
- ivo://CDS.VizieR/J/AJ/116/2805
- Title:
- H II regions in spiral galaxies
- Short Name:
- J/AJ/116/2805
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the results of low-dispersion optical spectroscopy of 186 HII regions spanning a range of radius in 13 spiral galaxies. Abundances for several elements (oxygen, nitrogen, neon, sulfur, and argon) were determined for 185 of the HII regions. As expected, low metallicities were found for the outlying HII regions of these spiral galaxies. Radial abundance gradients were derived for the 11 primary galaxies; similar to results for other spiral galaxies, the derived abundance gradients are typically -0.04 to -0.07dex/kpc.
- ID:
- ivo://CDS.VizieR/J/ApJ/755/40
- Title:
- HII regions in the Magellanic clouds from MCELS
- Short Name:
- J/ApJ/755/40
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We exploit ionization-parameter mapping (IPM) as a powerful tool to measure the optical depth of star-forming H II regions. Our simulations using the photoionization code CLOUDY and our new, SURFBRIGHT surface-brightness simulator demonstrate that this technique can directly diagnose most density-bounded, optically thin nebulae using spatially resolved emission-line data. We apply this method to the Large and Small Magellanic Clouds (LMC and SMC), using the data from the Magellanic Clouds Emission Line Survey. We generate new H II region catalogs based on photoionization criteria set by the observed ionization structure in the [S II]/[O III] ratio and H{alpha} surface brightness. The luminosity functions from these catalogs generally agree with those from H{alpha}-only surveys. We then use IPM to crudely classify all the nebulae into optically thick versus optically thin categories, yielding fundamental new insights into Lyman-continuum (LyC) radiation transfer.
- ID:
- ivo://CDS.VizieR/J/AJ/116/2246
- Title:
- HII regions in UGCA 86, 92, 105 and UGC 4115
- Short Name:
- J/AJ/116/2246
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Luminosity functions in H{alpha} have been measured for H II regions in the four dwarf galaxies UGCA 86, UGCA 92, UGCA 105, and UGC 4115 using both the traditional flux measurement method of fixed-threshold photometry (FTP) and the new method, percentage-of-peak photometry (PPP). The UGCA galaxies are members of the IC 342-Maffei 1 group. These two methods give significantly different results in galaxies in which significant numbers of peaks are associated with H II region complexes. The work demonstrates that fluxes from FTP can lead to biased luminosity functions and that PPP should, in general, be preferred. It is also shown that PPP luminosity functions are not very sensitive to atmospheric transparency, whereas those constructed from FTP can be, based on data taken under different atmospheric conditions. Results to date for six galaxies show that spirals and dwarfs have luminosity functions of similar shape, which implies that the distribution of the masses of star formation sites is largely independent of the mass, and by implication, the metallicity, of the host galaxy. As measured by PPP, the mean surface brightness of the lower luminosity H II regions grows as the one-third power of the flux grows, exactly as predicted for an ensemble in which the gas density does not vary systematically with the mass of the star cluster. For the brightest H II regions, however, the relation steepens, which implies that the most massive star clusters are formed out of the densest clouds.
