- ID:
- ivo://CDS.VizieR/J/ApJ/636/214
- Title:
- HII regions in dwarf irregular galaxies
- Short Name:
- J/ApJ/636/214
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present long-slit optical spectroscopy of 67 HII regions in 21 dwarf irregular galaxies to investigate the enrichment of oxygen, nitrogen, neon, sulfur, and argon in low-mass galaxies. Oxygen abundances are obtained via direct detection of the temperature-sensitive emission lines for 25 HII regions; for the remainder of the sample, oxygen abundances are estimated from strong-line calibrations. The direct abundance determinations are compared to the strong-line abundance calibrations of both McGaugh (1991ApJ...380..140M) and Pilyugin (2000A&A...362..325P).
Number of results to display per page
Search Results
- ID:
- ivo://CDS.VizieR/J/MNRAS/451/1307
- Title:
- HII regions in 10 galaxies
- Short Name:
- J/MNRAS/451/1307
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We have observed 10 interacting galaxy pairs using the Fabry-Perot interferometer GH{alpha}FaS (Galaxy H{alpha} Fabry-Perot system) on the 4.2m William Herschel Telescope (WHT) at the Observatorio del Roque de los Muchachos, La Palma. We present here the H{alpha} surface brightness, velocity and velocity dispersion maps for the 10 systems we have not previously observed using this technique, as well as the physical properties (sizes, H{alpha} luminosities and velocity dispersion) of 1259 HII regions from the full sample. We also derive the physical properties of 1054 HII regions in a sample of 28 isolated galaxies observed with the same instrument in order to compare the two populations of HII regions. We find a population of the brightest HII regions for which the scaling relations, for example the relation between the H{alpha} luminosity and the radius, are clearly distinct from the relations for the regions of lower luminosity. The regions in this bright population are more frequent in the interacting galaxies. We find that the turbulence, and also the star formation rate, are enhanced in the HII regions in the interacting galaxies. We have also extracted the H{alpha} equivalent widths for the HII regions of both samples, and we have found that the distribution of HII region ages coincides for the two samples of galaxies. We suggest that the SFR enhancement is brought about by gas flows induced by the interactions, which give rise to gravitationally bound gas clouds which grow further by accretion from the flowing gas, producing conditions favourable to star formation.
- ID:
- ivo://CDS.VizieR/J/A+A/481/645
- Title:
- HII regions in interacting galaxies
- Short Name:
- J/A+A/481/645
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Studies of interacting galaxies have shown that dwarf galaxies may be produced in tidal tails during collisions. Numerical simulations suggest that the total detachment of the tidal dwarf requires the companion's mass to be comparable to or higher than that of the parent galaxy. This would imply that minor mergers (interaction between unequal mass galaxies) might not form tidal dwarf galaxies (TDGs). The objectives of the paper is to analyse the main properties of a sample of 116 HII regions previously selected from H{alpha} images of 11 minor mergers of galaxies and discuss the nature of these regions comparing their properties with those observed in HII regions in normal and isolated galaxies and TDG candidates. Individual parameters such as: blue absolute magnitude, MB, H{alpha} luminosity, L(H{alpha}), star formation rate, SFR(H{alpha}) and mass, M/M_{sun}_ of these regions were derived and compared with those of the HII regions in normal isolated galaxies, as well as in tidal dwarf candidates.
- ID:
- ivo://CDS.VizieR/J/other/RAA/14.1393
- Title:
- HII regions in interacting system Arp 86
- Short Name:
- J/other/RAA/14.1
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present an analysis of the metallicity and star formation activities of HII regions in the interacting system Arp 86, based on the first scientific observations using multi-object spectroscopy with the 2.16m telescope at the Xinglong Observing Station. We find that the oxygen abundance gradient in Arp 86 is flatter than that in normal disk galaxies, which confirms that gas inflows caused by tidal forces during encounters can flatten the metallicity distributions in galaxies. The companion galaxy NGC 7752 is currently experiencing a galaxy-wide starburst with a higher star formation rate surface density than the main galaxy NGC 7753, which can be explained in that the companion galaxy is more susceptible to the effects of interaction than the primary. We also find that the galaxy 2MASX J23470758+2926531 has similar abundance and star formation properties to NGC 7753, and may be a part of the Arp 86 system.
- 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.
1527. HII regions in NGC 6814
- 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.
1528. HII Regions in NGC 4258
- 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)
1529. HII regions in NGC 628
- 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.
1530. HII regions in NGC 5055
- 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).
