- ID:
- ivo://CDS.VizieR/J/A+A/577/A21
- Title:
- Integral Field Spectroscopy of 8 BCGs
- Short Name:
- J/A+A/577/A21
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Blue Compact Galaxies (BCG) are gas rich, low luminosity, low metallicity systems, undergoing a violent burst of star formation. These galaxies offer us a unique opportunity to investigate collective star formation and its effects on galaxy evolution in a relatively simple environment. Spatially resolved spectrophotometric studies of BCGs are essential for a better understanding of the role of starburst-driven feedback processes on the kinematical and chemical evolution of low-mass galaxies near and far. We carry out an integral field spectroscopic study of a sample of BCGs, with the aim to probe the morphology, kinematics, dust extinction, and excitation mechanisms of their warm interstellar medium. Eight BCGs were observed with the VIMOS integral field unit at the Very Large Telescope using blue and orange grisms in high resolution mode. At a spatial sampling of 0.67 per spaxel we covered about 30x30-arcsec on the sky, with a wavelength range of 4150...7400{AA}. Emission lines were fitted with a single Gaussian profiles to measure their wavelength, flux, and width. From these data we built two-dimensional maps of the continuum and the most prominent emission-lines, as well as diagnostic line ratios, extinction, and kinematic maps. An atlas of emission-line fluxes and continuum emission; ionization, interstellar extinction, and electron density maps from line ratios; velocity and velocity dispersion fields. Additionally, from integrated spectroscopy, tables of the extinction corrected line fluxes and equivalent widths, diagnostic-line ratios, physical parameters and abundances for the brightest star-forming knots and for the whole galaxy.
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Search Results
- ID:
- ivo://CDS.VizieR/J/A+A/550/A114
- Title:
- Integrated spectroscopy of HRS galaxies
- Short Name:
- J/A+A/550/A114
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present long-slit integrated spectroscopy of 238 late-type galaxies belonging to the Herschel Reference Survey, a volume-limited sample representative of the nearby universe. This sample has a unique legacy value since it was ideally defined for any statistical study of the multifrequency properties of galaxies spanning a wide range in morphological type and luminosity. The spectroscopic observations cover the spectral range 3600-6900{AA} at a resolution R~=1000 and are thus suitable for separating both the underlying absorption from the emission of the H{beta} line and the two [NII] lines from the H{alpha} emission. We measured the fluxes and the equivalent widths of the strongest emission lines ([OII]{lambda}3727, H{beta}, [OIII]{lambda}4959 and [OIII]{lambda}5007, [NII]{lambda}6548, H{alpha}, [NII]{lambda}6584, [SII]{lambda}6717, and [SII]{lambda}6731). We used the data to study the distribution of the equivalent width of all the emission lines, of the Balmer decrement C(H{beta}), and of the observed underlying Balmer absorption under H{beta} (EWH{beta}_abs_) in this sample. Combining these new spectroscopic data with those available at other frequencies, we also study the dependence of C(H{beta}) and EWH{beta}_abs_ on morphological type, stellar mass, stellar surface density, star formation rate, birthrate parameter, and metallicity in galaxies belonging to different environments (fields vs. Virgo cluster). The distribution of the equivalent width of all the emission lines, of C(H{beta}) (or equivalently of A(H{alpha}), and of EWH{beta}_abs_ are systematically different in cluster and field galaxies. The Balmer decrement increases with the stellar mass, stellar surface density, metallicity, and star formation rate of the observed galaxies, while it is unexpectedly almost independent of the column density of the atomic and molecular gas. The dependence of C(H{beta}) on stellar mass is steeper than previously found in other works. The underlying Balmer absorption does not significantly change with any of these physical parameters.
- ID:
- ivo://CDS.VizieR/J/A+A/442/249
- Title:
- Integrated spectrum of NGC 7027
- Short Name:
- J/A+A/442/249
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present deep optical spectra of the archetypal young planetary nebula (PN) NGC 7027, covering a wavelength range from 3310 to 9160{AA}. The observations were carried out by uniformly scanning a long slit across the entire nebular surface, thus yielding average optical spectra for the whole nebula. A total of 937 emission features are detected. The extensive line list presented here should prove valuable for future spectroscopic analyses of emission line nebulae. The optical data, together with the archival IUE and ISO spectra, are used to probe the temperature and density structures and to determine the elemental abundances from lines produced by different excitation mechanisms.
- ID:
- ivo://CDS.VizieR/J/A+A/482/179
- Title:
- Interferometric study of SgrB2(N)
- Short Name:
- J/A+A/482/179
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Amino acids are building blocks of proteins and therefore key ingredients for the origin of life. The simplest amino acid, glycine (NH2CH2COOH), has long been searched for in the interstellar medium but has not been unambiguously detected so far. At the same time, more and more complex molecules have been newly found toward the prolific Galactic center source Sagittarius B2. Since the search for glycine has turned out to be extremely difficult, we aimed at detecting a chemically related species (possibly a direct precursor), amino acetonitrile (NH_2_CH_2_CN). With the IRAM 30m telescope we carried out a complete line survey of the hot core regions Sgr B2(N) and (M) in the 3mm range, plus partial surveys at 2 and 1.3mm. We analyzed our 30m line survey in the LTE approximation and modeled the emission of all known molecules simultaneously. We identified spectral features at the frequencies predicted for amino acetonitrile lines having intensities compatible with a unique rotation temperature. We also used the Very Large Array to look for cold, extended emission from amino acetonitrile.
- ID:
- ivo://CDS.VizieR/J/AJ/160/37
- Title:
- Intergalac. medium opacity from Lyman-break galaxies
- Short Name:
- J/AJ/160/37
- Date:
- 08 Dec 2021
- Publisher:
- CDS
- Description:
- We measure the effective opacity ({tau}_eff_) of the intergalactic medium from the composite spectra of 281 Lyman-break galaxies in the redshift range 2<~z<~3. Our spectra are taken from the COSMOS Ly{alpha} Mapping And Tomographic Observations survey derived from the Low Resolution Imaging Spectrometer on the W.M. Keck I telescope. We generate composite spectra in two redshift intervals and fit them with spectral energy distribution (SED) models composed of simple stellar populations. Extrapolating these SED models into the Ly{alpha} forest, we measure the effective Ly{alpha} opacity ({tau}_eff_) in the 2.02<~z<~2.44 range. At z=2.22, we estimate {tau}_eff_=0.159{+/-}0.001 from a power-law fit to the data. These measurements are consistent with estimates from quasar analyses at z<2.5 indicating that the systematic errors associated with normalizing quasar continua are not substantial. We provide a Gaussian processes model of our results and previous {tau}_eff_ measurements that describes the steep redshift evolution in {tau}_eff_ from z=1.5-4.
- ID:
- ivo://CDS.VizieR/J/ApJ/683/L115
- Title:
- Intermediate-line region in quasars
- Short Name:
- J/ApJ/683/L115
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We report on a systematic investigation of the H{beta} and FeII emission lines in a sample of 568 quasars within z<0.8 selected from the Sloan Digital Sky Survey quasar catalog (DR5, Cat. VII/252). The conventional broad H{beta} emission line can be decomposed into two components: one with intermediate velocity width and another with very broad width. The velocity shift and equivalent width of the intermediate-width component do not correlate with those of the very broad component of H{beta}, but its velocity shift and width do resemble FeII. Moreover, the width of the very broad component is roughly 2.5 times that of the intermediate-width component. These characteristics strongly suggest the existence of an intermediate-line region, whose kinematics seem to be dominated by infall, located at the outer portion of the broad-line region.
- ID:
- ivo://CDS.VizieR/J/A+A/622/A72
- Title:
- Intermediate-mass T Tau stars spectra
- Short Name:
- J/A+A/622/A72
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The origin of the fossil magnetic fields detected in 5 to 10% of intermediate-mass main sequence stars is still highly debated. We want to bring observational constraints to a large population of intermediate-mass pre-main sequence (PMS) stars in order to test the theory that convective-dynamo fields generated during the PMS phases of stellar evolution can occasionally relax into fossil fields on the main sequence. Using distance estimations, photometric measurements, and spectropolarimetric data from HARPSpol and ESPaDOnS of 38 intermediate-mass PMS stars, we determined fundamental stellar parameters (T_eff_, L and vsini) and measured surface magnetic field characteristics (including detection limits for non-detections, and longitudinal fields and basic topologies for positive detections). Using PMS evolutionary models, we determined the mass, radius, and internal structure of these stars. We compared different PMS models to check that our determinations were not model- dependant. We then compared the magnetic characteristics of our sample accounting for their stellar parameters and internal structures. Results: We detect magnetic fields in about half of our sample. About 90% of the magnetic stars have outer convective envelopes larger than ~25% of the stellar radii, and heavier than ~2% of the stellar mass. Going to higher mass, we find that the magnetic incidence in intermediate-mass stars drops very quickly, within a time-scale of the order of few times 0.1Myr. Finally, we propose that intermediate-mass T Tauri stars with large convective envelopes, close to the fully convective limit, have complex fields and that their dipole component strengths may decrease as the sizes of their convective envelopes decrease, similar to lower-mass T Tauri stars.
- ID:
- ivo://CDS.VizieR/J/ApJS/147/61
- Title:
- Interstellar Ca I absorption
- Short Name:
- J/ApJS/147/61
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present high-resolution (FWHM~0.3-1.5km/s) spectra, obtained with the AAT UHRF, the McDonald Observatory 2.7m coude spectrograph, and/or the KPNO coude feed, of interstellar Ca I absorption toward 30 Galactic stars. Comparisons of the column densities of Ca I, Ca II, K I, and other species - for individual components identified in the line profiles and also when integrated over entire lines of sight - yield information on relative electron densities and depletions (dependent on assumptions regarding the ionization equilibrium).
- ID:
- ivo://CDS.VizieR/III/148A
- Title:
- Interstellar lines catalogue
- Short Name:
- III/148A
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- A bibliographical catalogue of the interstellar lines has been prepared (2003 stars in our Galaxy, 86 stars in the Magellanic Clouds and 41 extragalactic objects), and 371 bibliographical references.
- ID:
- ivo://CDS.VizieR/J/MNRAS/367/1478
- Title:
- Interstellar NaI, TiII & CaIIK obs.
- Short Name:
- J/MNRAS/367/1478
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present an analysis of interstellar NaI ({lambda}_air_=3302.37 and 3302.98{AA}), TiII ({lambda}_air_=3383.76{AA}) and CaIIK ({lambda}_air_=3933.66{AA}) absorption features for 74 sightlines towards O- and B-type stars in the Galactic disc. The data were obtained from the Ultraviolet and Visual Echelle Spectrograph Paranal Observatory Project (UVES POP), at a spectral resolution of 3.75km/s and with mean signal-to-noise ratios per pixel of 260, 300 and 430 for the NaI, TiII and CaII observations, respectively. Interstellar features were detected in all but one of the TiII sightlines and all of the CaII sightlines. The dependence of the column density of these three species with distance, height relative to the Galactic plane, HI column density, reddening and depletion relative to the solar abundance has been investigated. We also examine the accuracy of using the NaI column density as an indicator of that for HI. In general, we find similar strong correlations for both Ti and Ca, and weaker correlations for Na. Our results confirm the general belief that Ti and Ca occur in the same regions of the interstellar medium (ISM) and also that the TiII/CaII ratio is constant over all parameters. We hence conclude that the absorption properties of Ti and Ca are essentially constant under the general ISM conditions of the Galactic disc.
