- ID:
- ivo://CDS.VizieR/J/A+A/529/A149
- Title:
- HII regions in low-metallicity galaxies
- Short Name:
- J/A+A/529/A149
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present deep spectroscopy of a large sample of low-metallicity emission-line galaxies. The main goal of this study is to derive element abundances in these low-metallicity galaxies. We analyze 121 VLT spectra of HII regions in 46 low-metallicity emission-line galaxies. Of these spectra 83 are archival VLT/FORS1+UVES spectra of HII regions in 31 low-metallicity emission-line galaxies that are studied for the first time with standard direct methods to determine the electron temperatures, the electron number densities, and the chemical abundances.
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Search Results
- ID:
- ivo://CDS.VizieR/J/ApJS/73/661
- Title:
- H II regions in M 101
- Short Name:
- J/ApJS/73/661
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- A previous survey of the H II regions in M101 (Hodge and Kennicutt) has been extended by a series of CCD images and image tube plates of the galaxy, approximately tripling the number of known emission regions. This paper provides maps and a catalog of a total of 1264 H II regions in M101.
203. HII Regions in M51
- ID:
- ivo://CDS.VizieR/J/A+A/309/446
- Title:
- HII Regions in M51
- Short Name:
- J/A+A/309/446
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- A deeper detection of the spiral structure of the Sbc galaxy M 51 is the main goal of this paper. New UV data in the 2000A range were obtained with a high altitude balloon of the Laboratoire d'Astronomie Spatiale de Marseille and the Observatoire de Geneve, (LAS-OG). The data reveal the location of hot, evolved low-mass stars predominantly along the outside edge of, and down stream from, the spiral arms defined by the string of HII regions. Since these stars have a relatively well-defined age compared to the "mixed" population of stars seen in the arms when observed in visible light, the UV data is well-suited to derive time-scales of spiral arm components. In particular, the relation between spiral structure and star formation, which is at least partly due to the density wave shock mechanism, can be studied from the differential positions of the low-mass stars observed in the UV and the massive stars coexisting with the ionized gas. To facilitate such detailed UV-H{alpha} comparison, we have also carried out new deep integrations, photometry, and accurate mapping of the H{alpha} emission. A catalogue of 478 HII regions in M 51 has been established from the analysis of narrow band H{alpha} images taken with a combination of the Special Astronomical Observatory (SAO) Russian image tube, and the Observatoire de Marseille (OM) focal reducer f/1.5 (9m equivalent focal length) attached at the prime focus of the 6-m telescope of the SAO. The radial and tangential shifts of the main and secondary spiral structures in UV and H{alpha} are also compared with other spiral tracers. The displacements observed in these observations are compatible with a scenario in which the star formation is triggered by the density wave.
- 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.
- 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/268/419
- Title:
- HII Regions in NGC 4258
- Short Name:
- J/A+A/268/419
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- (no description available)
- 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/RMxAA/44.161
- Title:
- HII regions in NGC 5055
- Short Name:
- J/other/RMxAA/44
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- In this paper, using CCD observations of the galaxy NGC 5055 in the emission lines of Halpha and Hbeta (Rozas, 2007RMxAA, submitted), together with CCD observations in the narrow-band filters of [OII], [OIII], [SII], and S[III] lines we have calculated the equivalent widths, excitations, ionization hardness, ionization parameters and metallicities for the regions catalogued in Rozas (2007RMxAA, submitted).
- 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/AJ/106/56
- Title:
- HII regions in NGC 6814
- Short Name:
- J/AJ/106/56
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a new Halpha image of high quality of the grand-design galaxy NGC 6814, and describe statistical properties of the HII region population. We have determined positions, angular sizes, and calibrated fluxes of 735 individual HII regions. We construct luminosity functions (LFs) for the complete sample, separately for arm and interarm regions, and for HII regions within and outside the limiting radius corresponding to the bright optical disk. The slope of the LF for the complete sample agrees well with values published for other Sbc and Sc galaxies. LFs for HII regions in the arms, in the interarm regions, in the inner part, and in the outer part of the galaxy all have the same slopes. We show and discuss the diameter distribution of the HII regions, both for the complete sample and for the separate arm, interarm, inner, and outer disk samples. There is no evidence for a different population of HII regions in the spiral arms, nor is there evidence for the existence of a significant population of density-bounded HII regions. We discuss implications for massive star forming processes in this galaxy, and discuss possible differences from other grand-design spirals.
