- ID:
- ivo://CDS.VizieR/J/MNRAS/477/4152
- Title:
- H II region candidates in NGC628
- Short Name:
- J/MNRAS/477/4152
- Date:
- 17 Jan 2022 00:25:45
- Publisher:
- CDS
- Description:
- This is the first paper of a series dedicated to nebular physics and the chemical evolution of nearby galaxies by investigating large samples of H II regions with the Canada-France-Hawaii Telescope imaging spectrograph SITELLE (Spectro-Imageur a Transformee de Fourier pour l'Etude en Long et en Large des raies d'Emission). We present a technique adapted to imaging spectroscopy to identify and extract parameters from 4285 H II region candidates found in the disc of NGC 628. Using both the spatial and spectral capabilities of SITELLE, our technique enables the extraction of the position, dust extinction, velocity, H{alpha} profile, diffuse ionized gas (DIG) background, luminosity, size, morphological type, and the emission-line fluxes for individual spaxels and the integrated spectrum for each region. We have produced a well-sampled H II region luminosity function and studied its variation with galactocentric radius and level of the DIG background. We found a slope {alpha} of -1.12+/-0.03 with no evidence of a break at high luminosity. Based on the width of the region profile, bright regions are rather compact, while faint regions are seen over a wide range of sizes. The radius function reveals a slope of -1.81+/-0.02. BPT diagrams of the individual spaxels and integrated line ratios confirm that most detections are H II regions. Also, maps of the line ratios show complex variations of the ionization conditions within HII regions. All this information is compiled in a new catalogue for HII regions. The objective of this data base is to provide a complete sample which will be used to study the whole parameter space covered by the physical conditions in active star-forming regions.
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Search Results
- ID:
- ivo://CDS.VizieR/J/MNRAS/297/255
- Title:
- HII region catalogue of M100
- Short Name:
- J/MNRAS/297/255
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- From a new mosaic image in the H-{alpha} line of the complete disc of the spiral galaxy M100, a catalogue is composed listing 1948 individual HII regions. For each HII region, the catalogue gives its position relative to the centre of the galaxy, its deprojected distance to the centre, its radius, and its calibrated luminosity. An indication is included as to whether the HII region is located in the arms, between them, or in the circumnuclear star-forming region. The H-{alpha} image of M100 was obtained during two observing runs with the 4.2m WHT on La Palma, using the TAURUS camera in imaging mode. Since the field of view in this setup is limited by the filter size to around 5' diameter, four fields of the galaxy were imaged, two (eastern half of M100) during the night of 27 May 1991, and two (western half) during the night of 14 March 1992. Narrow band redshifted H-{alpha} filters with width of 15{AA} were used for the observations, centred at 6601{AA} for the H-{alpha} line observations (redshifted using the galaxy's systemic velocity of 1571km/s) and at 6577{AA} and 6565{AA} for the continuum. Exposure times were 1200 seconds for both the on-line and the continuum image on the first night, and 2x900 seconds on the second night. An EEV CCD chip was used during both observing runs, with a projected pixel size of 0.279arcsec, and a size of 1180x1280 pixels.
- ID:
- ivo://CDS.VizieR/J/A+AS/135/145
- Title:
- HII region catalogue of NGC 7479
- Short Name:
- J/A+AS/135/145
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- HII region catalogue of the barred galaxy NGC 7479. The catalogue contains the position, mean radius and the calibrated H-alpha luminosity of each HII region. The HII region catalogue has been composed using a new semi-automated technique applied to a high quality continuum-subtracted H-alpha image of the galaxy obtained from observations through the TAURUS camera in imaging mode with the 4.2m WHT on La Palma. An EEV CCD 7 detector was used with a projected pixel size of 0.279". More details about the reduction and the catalogue production procedures are given in the paper.
- ID:
- ivo://CDS.VizieR/J/A+A/354/823
- Title:
- HII region catalogue of NGC 3359
- Short Name:
- J/A+A/354/823
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- From an H-{alpha} image of the spiral barred galaxy NGC 3359, an HII region catalogue is composed. The catalogue comprises the position, mean radius and the calibrated H-alpha luminosity of each HII region. The observations of the image of NGC 3359 in H-{alpha} were carried out in February 1996, on the Isaac Newton telescope in La Palma in the context of the BARS international time project of the Canary Islands Observatories. A CCD TeK-7 detector was used with a projected pixel size of 0.59".
- ID:
- ivo://CDS.VizieR/J/MNRAS/500/2359
- Title:
- HII region emission-line fluxes analysis
- Short Name:
- J/MNRAS/500/2359
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Studies of gas-phase radial metallicity profiles in spirals published in the last decade have diminished the importance of galactic bars as agents that mix and flatten the profiles, contradicting results obtained in the 1990s. We have collected a large sample of 2831 published HII region emission-line fluxes in 51 nearby galaxies, including objects both with and without the presence of a bar, with the aim of revisiting the issue of whether bars affect the radial metal distribution in spirals. In this first paper of a series of two, we present the galaxy and the HII region samples. The methodology is homogeneous for the whole data sample and includes the derivation of HII region chemical abundances, structural parameters of bars and discs, galactocentric distances, and radial abundance profiles. We have obtained O/H and N/O abundance ratios from the Te-based (direct) method for a sub-sample of 610 regions, and from a variety of strong-line methods for the whole HII region sample. The strong-line methods have been evaluated in relation to the Te-based one from both a comparison of the derived O/H and N/O abundances for individual HII regions, and a comparison of the abundance gradients derived from both methodologies. The median value and the standard deviation of the gradient distributions depend on the abundance method, and those based on the O3N2 indicator tend to flatten the steepest profiles, reducing the range of observed gradients. A detailed analysis and discussion of the derived O/H and N/O radial abundance gradients and y-intercepts for barred and unbarred galaxies is presented in the companion Paper II (Zurita et al., 2021MNRAS.500.2380Z). The whole HII region catalogue including emission-line fluxes, positions and derived abundances is made publicly available on the CDS VizieR facility, together with the radial abundance gradients for all galaxies.
- ID:
- ivo://CDS.VizieR/J/A+A/624/A100
- Title:
- HII region G24.78+0.08 A1 images
- Short Name:
- J/A+A/624/A100
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The earliest phases of the evolution of a massive star are closely related to the developement of an HII region. Hypercompact HII regions are the most interesting in this respect because they are very young, and hence best suited to study the beginning of the expansion of the ionised gas inside the parental core. We have analysed the geometrical and physical structure of the hypercompact HII region G24.78+0.08 A1, making use of new continuum and hydrogen recombination line data (H41{alpha}, H63{alpha}, H66{alpha}, H68{alpha}) and data from the literature (H30{alpha}, H35{alpha}). We fit the continuum spectrum with a homogenous, isothermal shell of ionised gas at 10^4^K and derive the size of the HII region and the Lyman continuum luminosity of the ionising star. We also fit the recombination line spectra emitted from the same shell with a model taking into account expansion at constant speed. The best fits to the continuum and line spectra allow the derivation of the Lyman continuum luminosity of the ionising star, HII region size, geometrical thickness of the shell, and expansion velocity. Comparison between the 5cm and 7mm brightness temperature distributions demonstrates that a thin layer of ionised gas of a few 1000K at the surface of the HII region is necessary to reproduce the morphology of the continuum emission at both wavelengths. We confirm that the G24 A1 hypercompact HII region consists of a thin shell ionised by an O9.5 star. The shell is expanding at a speed comparable to the sound speed in the ionised gas. The radius of the HII region exceeds the critical value needed to trap the ionised gas by the gravitational field of the star, consistent with the observed expansion.
- ID:
- ivo://CDS.VizieR/J/ApJ/774/117
- Title:
- HII region kinematic distances
- Short Name:
- J/ApJ/774/117
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We make a comprehensive study of H I absorption toward H II regions located within |l|<10{deg}. Structures in the extreme inner Galaxy are traced using the longitude-velocity space distribution of this absorption. We find significant H I absorption associated with the Near and Far 3kpc Arms, the Connecting Arm, Bania's Clump 1, and the HI Tilted Disk. We also constrain the line-of-sight distances to H II regions, by using H I absorption spectra together with the H II region velocities measured by radio recombination lines.
- ID:
- ivo://CDS.VizieR/J/ApJ/602/200
- Title:
- HII regions abundances in blue compact galaxies
- Short Name:
- J/ApJ/602/200
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We use spectroscopic observations of a sample of 82 HII regions in 76 blue compact galaxies to determine the primordial helium abundance Yp and the slope dY/dZ from the Y-O/H linear regression. To improve the accuracy of the dY/dZ measurement, we have included new spectrophotometric observations of 33 HII regions that span a large metallicity range, with oxygen abundance 12+log(O/H) varying between 7.43 and 8.30 (Z_{sun}_/30<=Z<=Z_{sun}_/4). Most of the new galaxies were selected from the First Byurakan, the Hamburg/SAO, and the University of Michigan objective prism surveys.
- ID:
- ivo://CDS.VizieR/J/MNRAS/445/1412
- Title:
- HII regions and GMC in the Antennae
- Short Name:
- J/MNRAS/445/1412
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We have combined observations of the Antennae galaxies from the radio interferometer ALMA (Atacama Large Millimeter/submillimeter Array) and from the optical interferometer GH{alpha}FaS (Galaxy H{alpha} Fabry-Perot System). The two sets of observations have comparable angular and spectral resolutions, enabling us to identify 142 giant molecular clouds (GMCs) and 303 HII regions. We have measured, and compared, their basic physical properties (radius, velocity dispersion, luminosity).
- ID:
- ivo://CDS.VizieR/J/A+AS/131/319
- Title:
- HII regions catalogue
- Short Name:
- J/A+AS/131/319
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Several galaxies were studied at Observatoire de Marseille using the films obtained at the 6m telescope with the Great Focal Reducer installed at the prime focus of the russian telescope. We thought that before we retire, it should be of some interest for the astronomical community to find in a single catalogue all the data we published to facilitate the research. (see hereunder the references). We give in this catalogue the data of the following galaxies: M 33, M 51, M 81, NGC 2403, NGC 4258 and NGC 7331. NGC 4258 was not studied with the 6m telescope, but we added its results because it was published by the same team using the same softwares. For NGC 7331 (see Petit 1998, Cat. J/A+AS/131/317). The flux values are followed by*; that means that they are not absolute fluxes like in the other publications. In order to make the catalogue easier to consult, we homogeneised the data. So, one can find some slight differences between the original data and the catalogue ones. The details of these modifications are precised in the Readme file associated to the catalogue in the data base. We did not keep the remarks so it is necessary to look at the original publication to find the full information. We give the whole references hereunder to facilitate the research of the original articles.
