- ID:
- ivo://CDS.VizieR/J/A+A/573/A65
- Title:
- Spectra of young planetary nebulae
- Short Name:
- J/A+A/573/A65
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The evolution of central stars of planetary nebulae was so far documented in just a few cases. However, spectra collected a few decades ago may provide a good reference for studying the evolution of central stars using the emission line fluxes of their nebulae. We investigated evolutionary changes of the [OIII] 5007{AA} line flux in the spectra of planetary nebulae. We compared nebular fluxes collected during a decade or longer. We used literature data and newly obtained spectra. A grid of Cloudy models was computed using existing evolutionary models, and the models were compared with the observations. An increase of the [OIII] 5007{AA} line flux is frequently observed in young planetary nebulae hosting H-rich central stars. The increasing nebular excitation is the response to the increasing temperature and hardening radiation of the central stars. We did not observe any changes in the nebular fluxes in the planetary nebulae hosting late-type Wolf-Rayet (WR) central stars. This may indicate a slower temperature evolution (which may stem from a different evolutionary status) of late-[WR] stars. In young planetary nebulae with H-rich central stars, the evolution can be followed using optical spectra collected during a decade or longer. The observed evolution of H-rich central stars is consistent with the predictions of the evolutionary models provided in the literature. Late-[WR] stars possibly follow a different evolutionary path.
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- ID:
- ivo://CDS.VizieR/J/AJ/103/267
- Title:
- Spectrocopy of hot stars in galactic halo
- Short Name:
- J/AJ/103/267
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The paper presents spectroscopy for 769 hot stars from the HK objective-prism/interference-filter survey of Beers et al. (1985), 193 of which have also available broadband UBV colors. When available, photometric information is used to obtain estimates of the surface temperature for degenerates and for O- and B-type subdwarfs, based on previously derived calibrations. Several extremely hot (T(eff) greater than 50,000 K) He-rich sdO stars are identified. Out of 769 stars in this sample, 551 are clearly identified on the basis of their Balmer line profiles as field horizontal-branch (FHB) or mid-to late-type A stars. The A stars exhibit rotation and line-of-sight dispersion consistent with membership in the galactic thick disk. The FHB stars exhibit kinematic properties which suggest a transition from thick disk to halo.
- ID:
- ivo://CDS.VizieR/J/A+A/285/1
- Title:
- Spectrographic study of Kiso UV-excess galaxies
- Short Name:
- J/A+A/285/1
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- (no description available)
- ID:
- ivo://CDS.VizieR/VII/141
- Title:
- Spectrophotometric Atlas of Galaxies
- Short Name:
- VII/141
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- This catalog contains 56 spectra: 55 galaxy spectra, and one night sky spectrum, which is included for users wishing to check for low-level spurious features in the galaxy spectra. The file "spectra.dat" contains a summary of the spectra. The user should consult the paper for details of the observations and a discussion of the limitations of the spectrophotometry. The spectra are integrated measurements made with apertures comparable to the diameters of the galaxies. The original spectra have been combined, rebinned to a common wavelength scale, and normalized in flux to unity at a reference wavelength of 555nm. An atmospheric extinction correction has been applied to the data, but otherwise they are not corrected for reddening, redshift, etc. The spectral range covered is 365-710 nm and the resolution is 5-8{AA}. Each spectrum consists in 1726 normalized flux values spaced each 2{AA}, stored as a file in the subdirectory "sp". Tests show that the spectrophotometry is accurate to the few percent level over small wavelength regions, and at the 10% level over the entire wavelength range. Although the data are useful for a variety of applications, the user should be forewarned that they may not be suitable for applications requiring precision colors over a long wavelength baseline (e.g., computation of K-corrections, some spectral synthesis applications).
- ID:
- ivo://CDS.VizieR/J/A+A/366/68
- Title:
- Spectrophotometric indices from galaxy bulges
- Short Name:
- J/A+A/366/68
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We have measured Mg_2_, Fe5270 and Fe5335 spectrophotometric indices (LICK system) in the bulge of 89 galaxies, mostly spirals from the Heraudeau sample. The indices are reduced to a null velocity dispersion and normalized to an aperture of 0.2h^-1^kpc. The mean errors are 0.009 mag on Mg_2_, and 0.3{AA} on the iron indices. These measurements almost double the amount of similar data already available on spiral galaxies. Our data confirm the existence of the relation between Mg_2_ and sigma_0_, the central stellar velocity dispersion; and we find an even tighter relation between Mg_2_ and Vmaxrot, the maximum rotational velocity of the galaxy, deduced from HI observations. For the most massive bulges these correlations may be interpreted as a mass-metallicity relation. However, the presence of young stellar populations, traced by the detection of [OIII]{lambda}500.7nm emission, provides a clear evidence that age effects play a role. Since the contribution of the young population is anti-correlated with the mass of the galaxy, it continues the Mg_2_ vs. sigma_0_ relation toward the low sigma_0_ and globally increases its slope. We present also evidence for a new positive correlation between Fe indices and sigma_0_ and for a significant correlation between the line strength indices and the total or disk luminosity. We propose to model the whole sequence of bulges within the following framework: Bulges are composed of a primary population formed prior to the disk during the initial collapse and a secondary population formed along the evolution. The whole family of bulges can be classified in three classes: (A) The bulges dominated by a young population are generally small, have ionized gas, low velocity dispersion and low line strengths. (B) The bulges dominated by the primary population lie along the mass metallicity sequence defined for elliptical galaxies. (C) The bulges where the secondary population is significant are less Mg-overabundant than B-type bulges and deviate from the Mg_2_ vs. sigma_0_ relation of elliptical galaxies. The original data are available in Hypercat: http://www-obs.univ-lyon1.fr/hypercat The tables of measurements and the extracted 1D spectra are also available in the present archive set.
- ID:
- ivo://CDS.VizieR/J/AJ/158/147
- Title:
- Spectrophotometric parallaxes with linear models
- Short Name:
- J/AJ/158/147
- Date:
- 07 Jan 2022 11:19:14
- Publisher:
- CDS
- Description:
- With contemporary infrared spectroscopic surveys like APO Galactic Evolution Experiment (APOGEE), red-giant stars can be observed to distances and extinctions at which Gaia parallaxes are not highly informative. Yet the combination of effective temperature, surface gravity, composition, and age-all accessible through spectroscopy - determines a giant's luminosity. Therefore spectroscopy plus photometry should enable precise spectrophotometric distance estimates. Here we use the overlap of APOGEE, Gaia, the Two Micron All Sky Survey (2MASS), and the Wide-field Infrared Survey Explorer (WISE) to train a data-driven model to predict parallaxes for red-giant branch stars with 0<logg=<2.2 (more luminous than the red clump). We employ (the exponentiation of) a linear function of APOGEE spectral pixel intensities and multiband photometry to predict parallax spectrophotometrically. The model training involves no logarithms or inverses of the Gaia parallaxes, and needs no cut on the Gaia parallax signal-to-noise ratio. It includes an L1 regularization to zero out the contributions of uninformative pixels. The training is performed with leave-out subsamples such that no star's astrometry is used even indirectly in its spectrophotometric parallax estimate. The model implicitly performs a reddening and extinction correction in its parallax prediction, without any explicit dust model. We assign to each star in the sample a new spectrophotometric parallax estimate; these parallaxes have uncertainties of less than 15%, depending on data quality, which is more precise than the Gaia parallax for the vast majority of targets, and certainly any stars more than a few kiloparsec distance. We obtain 10% distance estimates out to heliocentric distances of 20 kpc, and make global maps of the Milky Way's disk.
- ID:
- ivo://CDS.VizieR/J/ApJ/883/157
- Title:
- Spectrophotometric redshifts of GOODS galaxies
- Short Name:
- J/ApJ/883/157
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We investigate the accuracy of 4000{AA}/Balmer-break based redshifts by combining Hubble Space Telescope (HST) grism data with photometry. The grism spectra are from the Probing Evolution And Reionization Spectroscopically survey with HST using the G800L grism on the Advanced Camera for Surveys. The photometric data come from a compilation by the 3D-HST collaboration of imaging from multiple surveys (notably, the Cosmic Assembly Near-infrared Deep Extragalactic Survey (CANDELS) and 3D-HST). We show evidence that spectrophotometric redshifts (SPZs) typically improve the accuracy of photometric redshifts by ~17%-60%. Our SPZ method is a template-fitting-based routine that accounts for correlated data between neighboring points within grism spectra via the covariance matrix formalism and also accounts for galaxy morphology along the dispersion direction. We show that the robustness of the SPZ is directly related to the fidelity of the D4000 measurement. We also estimate the accuracy of continuum-based redshifts, i.e., for galaxies that do not contain strong emission lines, based on the grism data alone ({sigma}_{Delta}z/(1+z)_^NMAD^<~0.06). Given that future space-based observatories like Wide Field InfraRed Survey Telescope and Euclid will spend a significant fraction of time on slitless spectroscopic observations, we estimate number densities for objects with |{Delta}z/(1+z_s_)|<=0.02. We predict ~700-4400 galaxies degree^-2^ for galaxies with D4000>1.1 and |{Delta}z/(1+z_s_)|<=0.02 to a limiting depth of i_AB_=24mag. This is especially important in the absence of an accompanying rich photometric data set like the existing one for the CANDELS fields, where redshift accuracy from future surveys will rely only on the presence of a feature like the 4000{AA}/Balmer breaks or the presence of emission lines within the grism spectra.
- ID:
- ivo://CDS.VizieR/J/ApJ/656/168
- Title:
- Spectrophotometry in NGC 5253
- Short Name:
- J/ApJ/656/168
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present echelle spectrophotometry of the blue compact dwarf galaxy NGC 5253 obtained with the VLT UVES. We have measured the intensities of a large number of permitted and forbidden emission lines in four zones of the central part of the galaxy. We detect faint CII and OII recombination lines, the first time that these are unambiguously detected in a dwarf starburst galaxy. The physical conditions of the ionized gas have been derived using a large number of different line intensity ratios.
- ID:
- ivo://CDS.VizieR/J/PAZh/23/409
- Title:
- Spectrophotometry of Mrk 509
- Short Name:
- J/PAZh/23/409
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Variability of the continuum, H{beta}, H{gamma} and HeII(4686{AA}) fluxes of the Seyfert I galaxy Mrk 509 is studied using spectra obtained on the 2.6-m telescope of the Crimean Astrophysical observatory from 1971-1993. All the measurements of fluxes are in the relative units normalized to the flux of [OIII](5007{AA}) taken equal to 100. The flux in the line [OIII](5007{AA}) is estimated in the interval of (5.7-7.6)*10^-13^erg/cm^2^/s=(5.7-7.6)*10^-16^W/m2. The variability amplitude in the continuum is higher than in the hydrogen lines.
- ID:
- ivo://CDS.VizieR/J/ApJS/164/81
- Title:
- Spectrophotometry of nearby galaxies
- Short Name:
- J/ApJS/164/81
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present integrated optical spectrophotometry for a sample of 417 nearby galaxies. Our observations consist of spatially integrated, S/N=10-100 spectroscopy between 3600 and 6900{AA} at ~8{AA} FWHM resolution. In addition, we present nuclear (2.5"x2.5") spectroscopy for 153 of these objects. Our sample targets a diverse range of galaxy types, including starbursts, peculiar galaxies, interacting/merging systems, dusty, infrared-luminous galaxies, and a significant number of normal galaxies. We use population synthesis to model and subtract the stellar continuum underlying the nebular emission lines. This technique results in emission-line measurements reliably corrected for stellar absorption. Here we present the integrated and nuclear spectra, the nebular emission-line fluxes and equivalent widths, and a comprehensive compilation of ancillary data available in the literature for our sample.
