- ID:
- ivo://CDS.VizieR/J/A+A/393/389
- Title:
- H{alpha} in HII regions in spiral galaxies
- Short Name:
- J/A+A/393/389
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- In this paper we study long slit spectra in the region of H{alpha} emission line of a sample of 111 spiral galaxies with recognizable and well defined spiral morphology and with a well determined environmental status, ranging from isolation to non-disruptive interaction with satellites or companions. The form and properties of the rotation curves are considered as a function of the isolation degree, morphological type and luminosity. The line ratios are used to estimate the metallicity of all the detected H II regions, thus producing a composite metallicity profile for different types of spirals. We have found that isolated galaxies tend to be of later types and lower luminosity than the interacting galaxies. The outer parts of the rotation curves of isolated galaxies tend to be flatter than in interacting galaxies, but they show similar relations between global parameters. The scatter of the Tully-Fisher relation defined by isolated galaxies is significantly lower than that of interacting galaxies. The [NII]/H{alpha} ratios, used as a metallicity indicator, show a clear trend between Z and morphological type, t, with earlier spirals showing higher ratios; this trend is tighter when instead of t the gradient of the inner rotation curve, G, is used; no trend is found with the change in interaction status. The Z-gradient of the disks depends on the type, being almost flat for early spirals, and increasing for later types. The [NII]/H{alpha} ratios measured for disk H II regions of interacting galaxies are higher than for normal/isolated objects, even if all the galaxy families present similar distributions of H{alpha} equivalent width.
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Search Results
- ID:
- ivo://CDS.VizieR/J/other/Ser/179.87
- Title:
- H{alpha} in HII regions of Holmberg IX
- Short Name:
- J/other/Ser/179.
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present observations of the nearby tidal dwarf galaxy Holmberg IX in M81 galaxy group in narrow band [SII] and Hα filters, carried out in March and November 2008 with the 2m RCC telescope at NAO Rozhen, Bulgaria. Our search for resident supernova remnants (identified as sources with enhanced [SII] emission relative to their Hα emission) in this galaxy yielded no sources of this kind, besides M&H 10-11 or HoIX X-1. Nevertheless, we found a number of objects with significant Hα emission that probably represent uncatalogued HII regions.
5853. Halpha maps of 3 LIRGS
- ID:
- ivo://CDS.VizieR/J/MNRAS/465/3461
- Title:
- Halpha maps of 3 LIRGS
- Short Name:
- J/MNRAS/465/3461
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We have observed three luminous infrared galaxy systems (LIRGS) which are pairs of interacting galaxies, with the Galaxy H{alpha} Fabry-Perot system (GH{alpha}FaS) mounted on the 4.2m William Herschel Telescope at the Roque de los Muchachos Observatory, and combined the observations with the Atacama Large Millimeter Array (ALMA) observations of these systems in CO emission to compare the physical properties of the star formation regions and the molecular gas clouds, and specifically the internal kinematics of the star forming regions. We identified 88 star forming regions in the H$\alpha$ emission data-cubes, and 27 molecular cloud complexes in the CO emission data-cubes. The surface densities of the star formation rate and the molecular gas are significantly higher in these systems than in non-interacting galaxies and the Galaxy, and are closer to the surface densities of the star formation rate and the molecular gas of extreme star forming galaxies at higher redshifts. The large values of the velocity dispersion also show the enhanced gas surface density. The HII regions are situated on the {Sigma}_SFR_-{sigma}_v_ envelope, and so are also in virial equilibrium. Since the virial parameter decreases with the surface densities of both the star formation rate and the molecular gas, we claim that the clouds presented here are gravitationally dominated rather than being in equilibrium with the external pressure.
- ID:
- ivo://CDS.VizieR/J/MNRAS/447/1126
- Title:
- Halpha measurements in Abell 2465
- Short Name:
- J/MNRAS/447/1126
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We investigate the star formation rate and its location in the major merger cluster Abell 2465 at z=0.245. Optical properties of the cluster are described in. Measurements of the H{alpha} and infrared dust emission of galaxies in the cluster were made with an interference filter centred on the redshifted line at a wavelength of 817 nm and utilized data from the Wide-field Infrared Survey Explorer satellite 12{mu}m band. Imaging in the Johnson U and B bands was obtained, and along with Sloan Digital Sky Survey u and r was used to study the blue fraction, which appears enhanced, as a further signature of star formation in the cluster. Star formation rates were calculated using standard calibrations. The total star formation rate normalized by the cluster mass, {Sigma}SFR/M_cl_ compared to compilations for other clusters indicate that the components of Abell 2465 lie above the mean z and M_cl_ relations, suggestive that interacting galaxy clusters have enhanced star formation. The projected radial distribution of the star-forming galaxies does not follow an NFW profile and is relatively flat indicating that fewer star-forming galaxies are in the cluster centre. The morphologies of the H{alpha} sources within R_200_ for the cluster as a whole indicate that many are disturbed or merging, suggesting that a combination of merging or harassment is working.
- ID:
- ivo://CDS.VizieR/J/A+A/643/A176
- Title:
- Halpha+[NII] imaging of Dorado galaxies
- Short Name:
- J/A+A/643/A176
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Dorado is a nearby, rich and clumpy galaxy group that extends for several degrees in the Southern Hemisphere. Although several studies have been dedicated to define its members, their kinematics, hot and cold gas content, in particular HI, their present star formation activity is yet unknown. For the first time, we map the H{alpha} distribution as a possible indicator of star formation activity of Dorado members a large fraction of which show interaction and merging signatures, regardless of their morphological type. With the 2.5m du Pont and the 1m Swope telescopes we obtained narrow-band, calibrated images of 14 galaxies, forming the backbone of the group, mapping H{alpha}+[NII] down to few 10^-17^erg/cm^2^/s/arcsec^2^. We estimated the galaxy star formation rate from the H{alpha} fluxes, corrected for Galaxy foreground extinction and [NII] contamination. H{alpha}+[NII] emission has been detected in all galaxies. HII regions clearly emerge in late-type galaxies, while in early-type galaxies the H{alpha}+[NII] emission is dominated by [NII], especially in the central regions. However, HII complexes are revealed in four early-type galaxies. Even in the compact group SGC 0414-5559, in the projected centre of Dorado, HII regions are found both through out the late-type galaxies and in the very outskirts of early-type members. Considering the Dorado group as a whole, we notice that the H{alpha}+[NII] equivalent width, a measure of the specific star formation, increases with the morphological type, from early to late-type members, although it remains lower that what observed in similar surveys of spiral galaxies. The star formation rate of the spiral members is in the range of what observed in similar galaxies surveys (James et al., 2004A&A...414...23J, Cat. J/A+A/414/23). However, in three spiral NGC 1536, PGC 75125 and IC 2058 the star formation rate is well below the median for their morphological classes. The star formation rate of some early-type members tends, at odds, to be higher than the average derived from H{alpha}+[NII] surveys of this morphological family. We detected in H{alpha}+[NII] all the early type galaxies observed and half of them show HII regions in well shaped rings as well as in their outskirts. These findings suggest that ETGs in this group are not dead galaxies: their star formation has not shutdown yet. Mechanisms such as gas stripping and gas accretion, through galaxy-galaxy interaction, seem relevant in modifying star formation in this evolutionary phase of Dorado.
- ID:
- ivo://CDS.VizieR/J/AJ/126/1286
- Title:
- H{alpha}+[NII] observations of M81 HII regions
- Short Name:
- J/AJ/126/1286
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- In a first of a series of studies of the H{alpha}+[NII] emission from nearby spiral galaxies, we present measurements of H{alpha}+[NII] emission from HII regions in M81. Our method uses large-field CCD images and long-slit spectra and is part of the ongoing Beijing-Arizona-Taipei-Connecticut Sky Survey (the BATC survey). The CCD images are taken with the National Astronomical Observatories of China (NAOC) 0.6/0.9m f/3 Schmidt telescope at the Xinglong Observing Station, using a multicolor filter set. The observations reported here were taken on 30 individual nights over the time period 1995 February 5 to 1997 February 19. Spectra of 10 of the brightest HII regions are obtained using the NAOC 2.16m telescope with a Tek 1024x1024 CCD, between 1997 April 9 and 11. The continua of the spectra are calibrated by flux-calibrated images taken from the Schmidt observations. We determine the continuum component of our H{alpha}+[NII] image via interpolation from the more accurately measured backgrounds (M81 starlight) obtained from the two neighboring (in wavelength) BATC filter images. We use the calibrated fluxes of H{alpha}+[NII] emission from the spectra to normalize this interpolated, continuum-subtracted H{alpha}+[NII] image. We estimate the zero-point uncertainty of the measured H{alpha}+[NII] emission flux to be 8%. A catalog of H{alpha}+[NII] fluxes for 456 HII regions is provided, with those fluxes being on a more consistent linear scale than previously available. The logarithmically binned H{alpha}+[NII] luminosity function of HII regions is found to have slope {alpha}=-0.70, consistent with previous results (which allowed {alpha}=-0.5 to -0.8). From the overall H{alpha}+[NII] luminosity of the HII regions, the star formation rate of M81 is found to be ~0.68M_{sun}_/yr, modulo uncertainty with extinction corrections.
- ID:
- ivo://CDS.VizieR/J/ApJ/647/128
- Title:
- H{alpha} observations of UV-selected galaxies
- Short Name:
- J/ApJ/647/128
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Using Halpha spectra of 114 rest-frame UV-selected galaxies at z~2, we compare inferred star formation rates (SFRs) with those determined from the UV continuum luminosity. After correcting for extinction using standard techniques based on the UV continuum slope, we find excellent agreement between the indicators, with <SFR_Ha_>=31M_{sun}_/yr and <SFR_UV_>=29M_{sun}_/yr. The agreement between the indicators suggests that the UV luminosity is attenuated by a typical factor of ~4.5 (ranging from no attenuation to a factor of 100 for the most obscured object in the sample), in good agreement with estimates of obscuration from X-ray, radio, and mid-IR data.
- ID:
- ivo://CDS.VizieR/J/ApJS/166/505
- Title:
- H{alpha} photometry of face-on galaxies
- Short Name:
- J/ApJS/166/505
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a survey of the photometric and kinematic properties of 39 nearby, nearly face-on disk galaxies. Our approach exploits echelle-resolution integral-field spectroscopy of the H{alpha} regions, obtained with DensePak on the WIYN 3.5m telescope Bench Spectrograph. These data are complemented by HI line profiles observed with the Nancay radio telescope for 25 of these sample galaxies. Twelve additional line widths are available for sample galaxies from the literature. In this paper, we introduce the goals of this survey, define the sample selection algorithm, and amass the integral field spectroscopic data and HI line widths. We establish spatially integrated H{alpha} line widths for the sample. We test the veracity of these spatially integrated line profiles by convolving narrowband imaging data with velocity field information for one of the sample galaxies, PGC 38268, and also by comparing to HI line profiles.
- ID:
- ivo://CDS.VizieR/II/24
- Title:
- H-{alpha} Photometry of Northern Late-Type Stars I.
- Short Name:
- II/24
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Observations are presented of the strength of the H-{alpha} absorption line in the spectra of approximately 600 northern F, G and K stars of differing luminosities and chemical compositions. Most of the stars in this catalogue were previously observed by Griffin and Redman (1960MNRAS.120..287G), Deeming (1960MNRAS.121...52D), and Griffin (1961MNRAS.122..181G). Data given in this catalog include HD number, MK spectral classification, high velocity, (B-V) color index, magnesium b ratio, sodium D line ratio and H-{alpha} ratio.
- ID:
- ivo://CDS.VizieR/II/22
- Title:
- H{alpha} photometry of Southern F-G dwarfs
- Short Name:
- II/22
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- H{alpha} photometry is presented for 172 southern F, G, and K type stars, mostly of luminosity classes V and IV. The bands measured, using a spectroscopic resolution of 3.4{AA}/mm, were: H{alpha}: 6546.5-6582.5{AA} comparison regions: 6469.0-6505.0{AA} and 6624.0-6660.0{AA}.