- ID:
- ivo://CDS.VizieR/J/ApJ/853/36
- Title:
- Spectroscopy obs. of 20 Planck gal. cluster cand.
- Short Name:
- J/ApJ/853/36
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present Gemini and Keck spectroscopic redshifts and velocity dispersions for 20 clusters detected via the Sunyaev-Zel'dovich (SZ) effect by the Planck space mission, with estimated masses in the range 2.3x10^14^M_{sun}_<M_500_^Pl^<9.4x10^14^M_{sun}_. Cluster members were selected for spectroscopic follow-up with Palomar, Gemini, and Keck optical and (in some cases) infrared imaging. Seven cluster redshifts were measured for the first time with this observing campaign, including one of the most distant Planck clusters confirmed to date, at z=0.782+/-0.010, PSZ2 G085.95+25.23. The spectroscopic redshift catalogs of members of each confirmed cluster are included as online tables. We show the galaxy redshift distributions and measure the cluster velocity dispersions. The cluster velocity dispersions obtained in this paper were used in a companion paper to measure the Planck mass bias and to constrain the cluster velocity bias.
Number of results to display per page
Search Results
- ID:
- ivo://CDS.VizieR/J/A+A/394/395
- Title:
- Spectroscopy of Abell 222 and Abell 223
- Short Name:
- J/A+A/394/395
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- This spectroscopic study of the neighboring massive clusters Abell 222 and Abell 223 is based on MOS using EMMI at the NTT. Photometry was obtained from WFI images taken with the ESO/MPG 2.2m telescope. Data for objects coincident with objects from Proust et al., 2000A&A...355..443P, is listed for comparison.
- ID:
- ivo://CDS.VizieR/J/AJ/124/2453
- Title:
- Spectroscopy of active galaxies in nearby clusters
- Short Name:
- J/AJ/124/2453
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We have used optical spectroscopy to investigate the active galaxy populations in a sample of 20 nearby Abell clusters. The targets were identified on the basis of 1.4GHz radio emission, which identifies them as either active galactic nuclei (AGNs) or galaxies forming stars at rates comparable to or greater than that of the Milky Way. The spectra were used to characterize the galaxies via their emission and absorption features.
1684. Spectroscopy of Be stars
- ID:
- ivo://CDS.VizieR/J/A+A/378/861
- Title:
- Spectroscopy of Be stars
- Short Name:
- J/A+A/378/861
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The 270 spectra enclosed are those used in the atlas and are described in the Table 1 of the paper: stars with magnitudes and spectral types, dates of observations and other data. All are normalized and corrected from the radial velocity due to Earth movement, but not corrected from the radial velocity of the star itself. The heliocentric Julian day of the mid-exposure appears in the header with a comment keyword. Very often it cannot be derived by a simple formula from the beginning and the time exposure, when the spectrum is the result of the sum of several successive ones, or when clouds have obliged to interrupt the exposure. For this reason, it is always indicated. The HD number of the star appears always in the name of the file, with additional letters to distinguish the different spectra of a same star. The tracings of the atlas (72 FITS files) are described in the subsection 2.4 of the paper and available with the electronic version.
- ID:
- ivo://CDS.VizieR/J/ApJ/700/1216
- Title:
- Spectroscopy of Be stars in open clusters
- Short Name:
- J/ApJ/700/1216
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We recently discovered a large number of highly active Be stars in the open cluster NGC 3766, making it an excellent location to study the formation mechanism of Be star disks. To explore whether similar disk appearances and/or disappearances are common among the Be stars in other open clusters, we present here multiple epochs of H{alpha} spectroscopy for 296 stars in eight open clusters. We identify 12 new transient Be stars and confirm 17 additional Be stars with relatively stable disks. By comparing the H{alpha} equivalent widths to the photometric y-H{alpha} colors, we present a method to estimate the strength of the H{alpha} emission when spectroscopy is not available. For a subset of 128 stars in four open clusters, we also use blue optical spectroscopy and available Stromgren photometry to measure their projected rotational velocities, effective temperatures, and polar surface gravities. We combine our Be star detections from these four clusters to investigate physical differences between the transient Be stars, stable Be stars, and normal B-type stars with no line emission. Both types of Be stars are faster rotating populations than normal B-type stars, and we find no significant physical differences between the transient and stable Be stars in our sample.
- ID:
- ivo://CDS.VizieR/J/AJ/152/40
- Title:
- Spectroscopy of 341 bright A- and B-type stars
- Short Name:
- J/AJ/152/40
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Binary stars and higher-order multiple systems are a ubiquitous outcome of star formation, especially as the system mass increases. The companion mass-ratio distribution is a unique probe into the conditions of the collapsing cloud core and circumstellar disk(s) of the binary fragments. Inside a~1000AU the disks from the two forming stars can interact, and additionally companions can form directly through disk fragmentation. We should, therefore, expect the mass-ratio distribution of close companions (a<~100AU) to differ from that of wide companions. This prediction is difficult to test using traditional methods, in particular, with intermediate-mass primary stars, for a variety of observational reasons. We present the results of a survey searching for companions to A- and B-type stars using the direct spectral detection method, which is sensitive to late-type companions within ~1'' of the primary and which has no inner working angle. We estimate the temperatures and surface gravity of most of the 341 sample stars and derive their masses and ages. We additionally estimate the temperatures and masses of the 64 companions we find, 23 of which are new detections. We find that the mass-ratio distribution for our sample has a maximum near q~0.3. Our mass-ratio distribution has a very different form than in previous works, where it is usually well-described by a power law, and indicates that close companions to intermediate-mass stars experience significantly different accretion histories or formation mechanisms than wide companions.
- ID:
- ivo://CDS.VizieR/J/AJ/145/102
- Title:
- Spectroscopy of bright M dwarfs in the northern sky
- Short Name:
- J/AJ/145/102
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a spectroscopic catalog of the 1564 brightest (J<9) M dwarf candidates in the northern sky, as selected from the SUPERBLINK proper motion catalog. Observations confirm 1408 of the candidates to be late-K and M dwarfs with spectral subtypes K7-M6. From the low ({mu}>40mas/yr) proper motion limit and high level of completeness of the SUPERBLINK catalog in that magnitude range, we estimate that our spectroscopic census most likely includes >90% of all existing, northern-sky M dwarfs with apparent magnitude J<9. Only 682 stars in our sample are listed in the Third Catalog of Nearby Stars (CNS3); most others are relative unknowns and have spectroscopic data presented here for the first time. Spectral subtypes are assigned based on spectral index measurements of CaH and TiO molecular bands; a comparison of spectra from the same stars obtained at different observatories, however, reveals that spectral band index measurements are dependent on spectral resolution, spectrophotometric calibration, and other instrumental factors. As a result, we find that a consistent classification scheme requires that spectral indices be calibrated and corrected for each observatory/instrument used. After systematic corrections and a recalibration of the subtype-index relationships for the CaH2, CaH3, TiO5, and TiO6 spectral indices, we find that we can consistently and reliably classify all our stars to a half-subtype precision. The use of corrected spectral indices further requires us to recalibrate the {zeta} parameter, a metallicity indicator based on the ratio of TiO and CaH optical bandheads. However, we find that our {zeta} values are not sensitive enough to diagnose metallicity variations in dwarfs of subtypes M2 and earlier (+/-0.5dex accuracy) and are only marginally useful at later M3-M5 subtypes (+/-0.2dex accuracy). Fits of our spectra to the Phoenix atmospheric model grid are used to estimate effective temperatures. These suggest the existence of a plateau in the M1-M3 subtype range, in agreement with model fits of infrared spectra but at odds with photometric determinations of T_eff_. Existing geometric parallax measurements are extracted from the literature for 624 stars, and are used to determine spectroscopic and photometric distances for all the other stars. Active dwarfs are identified from measurements of H{alpha} equivalent widths, and we find a strong correlation between H{alpha} emission in M dwarfs and detected X-ray emission from ROSAT and/or a large UV excess in the GALEX point source catalog. We combine proper motion data and photometric distances to evaluate the (U, V, W) distribution in velocity space, which is found to correlate tightly with the velocity distribution of G dwarfs in the solar neighborhood. However, active stars show a smaller dispersion in their space velocities, which is consistent with those stars being younger on average. Our catalog will be most useful to guide the selection of the best M dwarf targets for exoplanet searches, in particular those using high-precision radial velocity measurements.
- ID:
- ivo://CDS.VizieR/J/AJ/153/46
- Title:
- Spectroscopy of candidate members in Taurus
- Short Name:
- J/AJ/153/46
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Previous studies have found that ~1deg^2^ fields surrounding the stellar aggregates in the Taurus star-forming region exhibit a surplus of solar-mass stars relative to denser clusters like IC 348 and the Orion Nebula Cluster. To test whether this difference reflects mass segregation in Taurus or a variation in the initial mass function, we have performed a survey for members of Taurus across a large field (~40deg^2^) that was imaged by the Sloan Digital Sky Survey (SDSS). We obtained optical and near-infrared spectra of candidate members identified with those images and the Two Micron All Sky Survey, as well as miscellaneous candidates that were selected with several other diagnostics of membership. We have classified 22 of the candidates as new members of Taurus, which includes one of the coolest known members (M9.75). Our updated census of members within the SDSS field shows a surplus of solar-mass stars relative to clusters, although it is less pronounced than in the smaller fields toward the stellar aggregates that were surveyed for previously measured mass functions in Taurus. In addition to spectra of our new members, we include in our study near-IR spectra of roughly half of the known members of Taurus, which are used to refine their spectral types and extinctions. We also present an updated set of near-IR standard spectra for classifying young stars and brown dwarfs at M and L types.
- ID:
- ivo://CDS.VizieR/J/other/BASI/39.517
- Title:
- Spectroscopy of classical Be stars
- Short Name:
- J/other/BASI/39.
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a spectroscopic study of 150 Classical Be stars in 39 open clusters using medium resolution spectra in the wavelength range 3800-9000{AA}. One-third of the sample (48 stars in 18 clusters) has been studied for the first time. All these candidates were identified from an extensive survey of emission stars in young open clusters using slitless spectroscopy (Mathew et al., 2008MNRAS.388.1879M). This large data set covers CBe stars of various spectral types and ages found in different cluster environments in largely northern open clusters, and is used to study the spectral characteristics of CBe stars in cluster environments.
- ID:
- ivo://CDS.VizieR/J/ApJS/175/462
- Title:
- Spectroscopy of Coma early-type galaxies
- Short Name:
- J/ApJS/175/462
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The long-slit spectra obtained along the minor axis, offset major axis, and diagonal axis are presented for 12 E and S0 galaxies of the Coma Cluster drawn from a magnitude-limited sample studied before. The rotation curves, velocity dispersion profiles, and the H_3_ and H_4_ coefficients of the Hermite decomposition of the line-of-sight velocity distribution are derived. The radial profiles of the H{beta}, Mg, and Fe line strength indices are measured too. In addition, the surface photometry of the central regions of a subsample of four galaxies recently obtained with the Hubble Space Telescope is presented. The data will be used to construct dynamical models of the galaxies and study their stellar populations.
