- ID:
- ivo://CDS.VizieR/J/A+A/485/657
- Title:
- Physical parameters of Wolf-Rayet galaxies
- Short Name:
- J/A+A/485/657
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The availability of large spectroscopic datasets has opened up the possibility of constructing large samples of rare objects in a systematic manner. The goal of this study is to analyse the properties of galaxies showing Wolf-Rayet features in their optical spectrum using spectra from the Sloan Digital Sky Survey Release 6. With this unprecedentedly large sample we aim to constrain the properties of the Wolf-Rayet phase and its impact on the surrounding interstellar medium. We carried out very careful continuum subtraction on all galaxies with equivalent widths of H{beta}>2{AA} in emission and identify Wolf-Rayet features using a mixture of automatic and visual classification. We combined this with spectroscopic and photometric information from the SDSS and derive metal abundances using a number of methods.
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Search Results
- ID:
- ivo://CDS.VizieR/J/AJ/159/17
- Title:
- Physical properties of SFRs in NGC 3395/NGC 3396
- Short Name:
- J/AJ/159/17
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We report long-slit spectroscopy of the early major merger galaxies NGC 3395/NGC 3396. The spectra are consistent with those for star-forming galaxies, but there is some indication of LINER-like active galactic nucleus activity in the center of NGC 3396. The total star formation rate in the regions observed is 2.83 M_{sun}_/yr, consistent with estimates for the entire galaxies. The highest abundances are in the centers of the galaxies, with the abundances decreasing with distance. There is a correlation between high abundance and high ionization parameter, both of which can be attributed to the presence of massive stars. Modeling with SB 99 indicates the star-forming regions are younger than 10 Myr. There are 1000-2000 WNL stars in the system, along with several thousand O stars, consistent with the ages of the star-forming regions. The highest electron densities are found in young regions with high star formation rates. The electron temperatures are higher than results for non-interacting galaxies, which is probably due to shock waves produced by the galaxy-galaxy interaction, the outflow of gas from massive stars, and/or collisions between gas clouds in the galaxies. There is star formation in the bridge of material between the galaxies. These regions are among the youngest in the system and have low abundances, suggesting the gas was pulled from the outer parts of the galaxies. X-ray point sources, probably high-mass X-ray binaries, are associated with several star-forming regions.
- ID:
- ivo://CDS.VizieR/J/A+A/495/53
- Title:
- Physical properties of VVDS galaxies
- Short Name:
- J/A+A/495/53
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We want to derive the mass-metallicity relation of star-forming galaxies up to z~0.9, using data from the VIMOS VLT Deep Survey. The mass-metallicity relation is commonly understood as the relation between the stellar mass and the gas-phase oxygen abundance. Automatic measurement of emission-line fluxes and equivalent widths have been performed on the full spectroscopic sample of the VIMOS VLT Deep Survey. This sample is divided into two sub-samples depending on the apparent magnitude selection: wide (I_AB_<22.5) and deep (I_AB_<24). These two samples span two different ranges of stellar masses. Emission-line galaxies have been separated into star-forming galaxies and active galactic nuclei using emission line ratios. For the star-forming galaxies the emission line ratios have also been used to estimate gas-phase oxygen abundance, using empirical calibrations renormalized in order to give consistent results at low and high redshifts. The stellar masses have been estimated by fitting the whole spectral energy distributions with a set of stellar population synthesis models.
- ID:
- ivo://CDS.VizieR/J/ApJ/676/262
- Title:
- PKS1302-102 intergalactic absorption system
- Short Name:
- J/ApJ/676/262
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a detailed analysis of the intergalactic metal-line absorption systems in the archival HST STIS and FUSE ultraviolet spectra of the low-redshift quasar PKS 1302-102 (z_QSO_=0.2784). We supplement the archive data with CLOUDY ionization models and a survey of galaxies in the quasar field.
- ID:
- ivo://CDS.VizieR/J/A+A/595/A128
- Title:
- PKS 1830-211 OH+ and H2O+ spectra
- Short Name:
- J/A+A/595/A128
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We report the detection of OH^+^ and H_2_O^+^ in the z=0.89 absorber toward the lensed quasar PKS 1830-211. The abundance ratio of OH^+^ and H_2_O^+^ is used to quantify the molecular hydrogen fraction (fH2) and the cosmic-ray ionization rate of atomic hydrogen ({dzeta}_H_) along two lines of sight, located at ~2kpc and ~kpc to either side of the absorber's center. The molecular fraction decreases outwards, from ~0.04 to ~0.02, comparable to values measured in the Milky Way at similar galactocentric radii. For {dzeta}_H_, we find values of ~2x10^-14^s^-1^ and ~3x10^-15^s^-1^, respectively, which are slightly higher than in the Milky Way at comparable galactocentric radii, possibly due to a higher average star formation activity in the z=0.89 absorber. The ALMA observations of OH^+^, H_2_O^+^, and other hydrides toward PKS 1830-211 reveal the multi-phase composition of the absorbing gas. Taking the column density ratios along the southwest and northeast lines of sight as a proxy of molecular fraction, we classify the species ArH^+^, OH^+^, H_2_Cl^+^, H_2_O^+^, CH, and HF as tracing gases increasingly more molecular. Incidentally, our data allow us to improve the accuracy of H_2_O^+^ rest frequencies and thus refine the spectroscopic parameters.
- ID:
- ivo://CDS.VizieR/J/A+A/642/A59
- Title:
- PKS 1510-089 spectroscopic light curves
- Short Name:
- J/A+A/642/A59
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Reverberation results of the flat spectrum radio quasar PKS 1510-089 from 8.5 years of spectroscopic monitoring carried out at Steward Observatory over nine observing seasons between December 2008 and June 2017 are presented. Optical spectra show strong H{beta}, H{gamma}, and FeII emission lines overlying on a blue continuum. All the continuum and emission line light curves show significant variability with fractional root-mean-square variations of 37.30+/-0.06% (f_5100_), 11.88+/-0.29% (H{beta}), and 9.61+/-0.71% (H{gamma}); however, along with thermal radiation from the accretion disk, non-thermal emission from the jet also contributes to f5100. Several methods of time series analysis (ICCF, DCF, von Neumann, Bartels, javelin, 2) are used to measure the lag between the continuum and line light curves. The observed frame broad line region size is found to be 61.1^+4.0^_3.2_ (64.7^+27.1^_10.6_) light-days for H{beta} (H{gamma}). Using the line of 1262+/-247km/s measured from the root-mean-square spectrum, the black hole mass of PKS 1510-089 is estimated to be 5.71^+0.62^_0.58_x1^0^7M_{sun}_.
- ID:
- ivo://CDS.VizieR/J/other/RAA/18.140
- Title:
- Planetary nebulae in circumnuclear region of M31
- Short Name:
- J/other/RAA/18.1
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Planetary nebulae (PNe) are an important tool for studying the dynamics and chemical evolution of galaxies in the Local Universe, given their characteristic bright emission line spectra. The Andromeda Galaxy (M31) provides a unique laboratory for studying PNe in the circumnuclear region, thanks to its proximity and almost uniformly low line-of-sight extinction that ensures observations with high resolution and sensitivity. Using the WIYN/Hydra multi-fiber spectrograph, we have obtained optical (4119-6882{AA}) spectra of 77 PN candidates selected from Hubble Space Telescope narrow-band imaging, which are located within the central ~500 pc region of M31. Among these candidates, 49 (64%) are spectroscopically observed for the first time. The spectra of 300 previously known PNe and HII regions, which primarily reside in the disk, are also taken for comparison. All 77 circumnuclear PN candidates exhibit prominent emission lines, including [OIII] {lambda}5007, [NII] {lambda}6583, H{alpha} and H{beta}, strongly suggesting that they are genuine PNe. We measured the line fluxes, radial velocities and line widths for all objects, and found that the radial velocities of the circumnuclear PNe generally trace rotation of the inner bulge. We also estimated a dynamical mass of ~6.4+/-0.5x10^9^M_{sun}_ enclosed within an effective galactocentric radius of 340 pc, which is compatible with the previously estimated total stellar mass in this region.
1988. Planetary nebulae in M33
- ID:
- ivo://CDS.VizieR/J/ApJ/614/167
- Title:
- Planetary nebulae in M33
- Short Name:
- J/ApJ/614/167
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We report the results of a photometric and spectroscopic survey for planetary nebulae (PNs) over the entire body of the Local Group spiral galaxy M33. We use our sample of 152 PNs to show that the bright end of the galaxy's [OIII]{lambda}5007 planetary nebula luminosity function (PNLF) has the same sharp cutoff seen in other galaxies.
- ID:
- ivo://CDS.VizieR/J/A+A/419/563
- Title:
- Planetary nebulae near the Galactic Center
- Short Name:
- J/A+A/419/563
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We surveyed the central 4x4 degrees of the Galactic center for planetary nebulae in the light of [S III] {lambda}9532 and found 94 PNe that were not previously known, plus 3 that were previously identified as possible candidates. For 63 of these 97 objects, we obtained spectra that are consistent with highly reddened PN while the other 34 could not be recovered spectroscopically and remain unverified. Of the 94 candidates, 54 and 57 were detected via radio at 3 and 6cm, respectively. An additional 20 PNe candidates were found during follow-up H{alpha} imaging but have not yet been verified spectroscopically. Based on the properties of IRAS sources in this region of the Galaxy, and on the total luminosity of the Galactic bulge, the expected number of PNe is 250, only 50% more than the 160 PNe candidates now known. Thus, surveys for PNe in the bulge are approximately two-thirds complete with the remainder likely hidden behind dust.
- ID:
- ivo://CDS.VizieR/J/MNRAS/393/329
- Title:
- Planetary nebulae of NGC 4494
- Short Name:
- J/MNRAS/393/329
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present new Planetary Nebula Spectrograph observations of the ordinary elliptical galaxy NGC 4494, resulting in positions and velocities of 255 planetary nebulae out to seven effective radii (25kpc). We also present new wide-field surface photometry from MMT/Megacam, and long-slit stellar kinematics from VLT/FORS2.
