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1551. HII complexes optical and IR emissions
ID:
ivo://CDS.VizieR/J/MNRAS/444/757
Title:
HII complexes optical and IR emissions
Short Name:
J/MNRAS/444/757
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present an analysis of optical spectroscopy and infrared aperture photometry of more than 100 HII complexes in nine galaxies. Spectra obtained with the 6-m telescope of Special Astrophysical Observatory of the Russian Academy of Sciences are used along with archival data from Spitzer and several ground-based telescopes to infer a strength of polycyclic aromatic hydrocarbon (PAH) emission, age, properties of the UV radiation field, and metallicity of studied HII complexes. Physical properties (age, radiation field parameters, metallicity) are related to the F_8_/F_24_ ratio used as a proxy for the PAH abundance in order to reveal factors that may influence the PAH evolution in HII complexes. The well-known correlation between the F_8_/F_24_ ratio and metallicity is confirmed in the studied complexes. The infrared flux ratio also correlates with the [Oiii]{lambda}5007/H{beta} ratio which is often considered as an indicator of the radiation field hardness, but this correlation seems to be a mere reflection of a correlation between [Oiii]{lambda}5007/H{beta} and metallicity. In separate metallicity bins, the F_8_/F_24_ ratio is found to correlate with an age of an Hii complex, which is estimated from the equivalent width of H{beta} line. The correlation is positive for low-metallicity complexes and negative for high-metallicity complexes. Analysing various mechanisms of PAH formation and destruction in the context of found correlations, we suggest that PAH abundance is likely altered by the UV radiation within HII complexes, but this is not necessarily due to their destruction. If PAHs can also form in Hii complexes due to some processes like aromatization, photodestruction, shattering and sputtering of very small grains, the net F_8_/F_24_ ratio is determined by a balance between all these processes that can be different at different metallicities.
1552. HII galaxies narrow-band Hbeta images
ID:
ivo://CDS.VizieR/J/A+A/476/89
Title:
HII galaxies narrow-band Hbeta images
Short Name:
J/A+A/476/89
Date:
21 Oct 2021
Publisher:
CDS
Description:
Our aims is to create a catalog of images of HII galaxies and their individual star-formation regions in order to study the distribution of the gas emission and their underlying stellar continuum. We have used H{beta} narrow-band images of 43 selected HII galaxies obtained at ESO NTT 3.58m telescope using the SUSI2 camera. Surface photometric H{beta} fluxes and equivalent widths for all objects and star-formation regions are presented in this catalog.
1553. HII galaxies spectrophotometric catalogue
ID:
ivo://CDS.VizieR/J/A+AS/91/285
Title:
HII galaxies spectrophotometric catalogue
Short Name:
J/A+AS/91/285
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present a spectrophotometric catalogue of 425 emission line galaxies discovered in objective prism surveys for which we derived redshifts, emission line intensities, equivalent widths, and absolute fluxes. The vast majority of objects in the catalogue are HII region-like galaxies (HII galaxies). In more than 80 HII galaxies the line [OIII]{lambda}4363 was measured with accuracy good enough to permit precise electron temperature determinations. The observational parameters that define the properties of HII galaxies as a class are characterized and discussed.
1554. HI in Byurakan blue compact galaxies
ID:
ivo://CDS.VizieR/J/A+AS/139/1
Title:
HI in Byurakan blue compact galaxies
Short Name:
J/A+AS/139/1
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present the results of a neutral hydrogen survey of 79 galaxies from a statistical sample of 88 Blue Compact Galaxies (BCGs) selected from the First and Second Byurakan objective prism surveys to have a HII region-like spectrum, an equivalent width of the [O III] {lambda}5007 line larger than ~50{AA}, and a velocity <=6000km/s. The detection rate for the statistical sample is 74%. HI masses range between 4x10^7^M_{sun}_ and 5x10^9^M_{sun}_ with the HI mass distribution peaking at 3x10^8^M_{sun}_. The full width at half-maximum of the HI profile varies between ~30km/s and 160km/s, with a mean of ~92km/s. These small widths are characteristic of dwarf galaxies. For comparison, we have also observed an additional 92 BCGs with weaker star formation and/or larger distances, and/or interesting astrophysical properties. These in general have larger widths and HI masses.
1555. HI in Local Supercluster dwarf galaxies
ID:
ivo://CDS.VizieR/J/A+A/506/677
Title:
HI in Local Supercluster dwarf galaxies
Short Name:
J/A+A/506/677
Date:
21 Oct 2021
Publisher:
CDS
Description:
We have observed 71 dwarf galaxies of low surface brightness using the 100-m radio telescope at Effelsberg in a search for new members of 27 northern galaxy groups with characteristic distances of 8 to 15Mpc. We present radial velocities, HI-fluxes, and HI line widths for 17 detected galaxies as well as upper limits for the remaining undetected objects.
1556. HI in nearby radio sources
ID:
ivo://CDS.VizieR/J/A+A/604/A43
Title:
HI in nearby radio sources
Short Name:
J/A+A/604/A43
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present an analysis of the properties of neutral hydrogen (HI) in 248 nearby (0.02<z<0.25) radio galaxies with S_1.4GHz_>30mJy and for which optical spectroscopy is available. The observations were carried out with the Westerbork Synthesis Radio Telescope as the last large project before the upgrade of the telescope with phased array feed receivers (Apertif). The sample covers almost four orders of magnitude in radio power from logP_1.4GHz_=22.5W/Hz and 26.2W/Hz. We detect HI in absorption in 27%+/-5.5% of the objects. The detections are found over the full range of radio power. However, the distribution and kinematics of the absorbing HI gas appear to depend on radio power, the properties of the radio continuum emission, and the dust content of the sources. Among the sources where HI is detected, gas with kinematics deviating from regular rotation is more likely found as the radio power increases.In the great majority of these cases, the HI profile is asymmetric with a significant blue-shifted component. This is particularly common for sources with logP_1.4GHz_>24W/Hz, where the radio emission is small, possibly because these radio sources are young. The same is found for sources that are bright in the mid-infrared, i.e. sources rich in heated dust.In these sources, the HI is outflowing likely under the effect of the interaction with the radio emission. Conversely, in dust-poor galaxies, and in sources with extended radio emission, at all radio powers we only detect HI distributed in a rotating disk. Stacking experiments show that in sources for which we do not detect HI in absorption directly, the HI has a column density that is lower than 3.5x10^17^(T_spin_/c_f_)cm^-2^. We use our results to predict the number and type of HI absorption lines that will be detected by the upcoming surveys of the Square Kilometre Array precursors and pathfinders (Apertif, MeerKAT, and ASKAP).
1557. H II region candidates in NGC628
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.
1558. HII region catalogue of M100
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.
1559. HII region catalogue of NGC 7479
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.
1560. HII region catalogue of NGC 3359
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".

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