- ID:
- ivo://CDS.VizieR/J/AJ/160/271
- Title:
- A catalog of ~30000 galaxies with ALFALFA-SDSS
- Short Name:
- J/AJ/160/271
- Date:
- 08 Dec 2021
- Publisher:
- CDS
- Description:
- We present a HI optical catalog of ~30000 galaxies based on the 100% complete Arecibo Legacy Fast Arecibo L-band Feed Array (ALFALFA) survey combined with data from the Sloan Digital Sky Survey (SDSS). Our goal is to facilitate the public use of the completed ALFALFA catalog by providing carefully determined matches to SDSS counterparts, including matches for ~10000 galaxies that do not have SDSS spectra. These identifications can provide a basis for further crossmatching with other surveys using SDSS photometric IDs as a reference point. We derive absolute magnitudes and stellar masses for each galaxy using optical colors combined with an internal reddening correction designed for small- and intermediate-mass galaxies with active star formation. We also provide measures of stellar masses and star formation rates based on infrared and/or ultraviolet photometry for galaxies that are detected by the Wide-field Infrared Survey Explorer and/or the Galaxy Evolution Explorer. Finally, we compare the galaxy population in the ALFALFA-SDSS sample with the populations in several other publicly available galaxy catalogs and confirm that ALFALFA galaxies typically have lower masses and bluer colors.
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- ID:
- ivo://CDS.VizieR/J/A+A/601/A10
- Title:
- A grid of MARCS model atmospheres for S stars
- Short Name:
- J/A+A/601/A10
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- S-type stars are late-type giants whose atmospheres are enriched in carbon and s-process elements because of either extrinsic pollution by a binary companion or intrinsic nucleosynthesis and dredge-up on the thermally-pulsing asymptotic giant branch. A grid of MARCS model atmospheres has been computed for S stars, covering the range 2700<=Teff(K)<=4000, 0.50<=C/O<0.99, 0<=logg<=5, [Fe/H]=0., -0.5dex, and [s/Fe]= 0, 1, and 2 dex (where the latter quantity refers to the global overabundance of s-process elements). The MARCS models make use of a new ZrO line list. Synthetic spectra computed from these models are used to derive photometric indices in the Johnson and Geneva systems, as well as TiO and ZrO band strengths. A method is proposed to select the model best matching any given S star, a non-trivial operation since the grid contains more than 3500 models covering a five-dimensional parameter space. The method is based on the comparison between observed and synthetic photometric indices and spectral band strengths, and has been applied on a vast subsample of the Henize sample of S stars. Our results confirm the old claim by Piccirillo (1980MNRAS.190..441P) that ZrO bands in warm S stars (Teff > 3200K) are not caused by the C/O ratio being close to unity, as traditionally believed, but rather by some Zr overabundance. The TiO and ZrO band strengths, combined with V-K and J-K photometric indices, are used to select Teff, C/O, [Fe/H] and [s/Fe]. The Geneva U-B_1 and B_2-V_1 indices (or any equivalent) are good at selecting the gravity. The defining spectral features of dwarf S stars are outlined, but none is found among the Henize S stars. More generally, it is found that, at Teff=3200K, a change of C/O from 0.5 to 0.99 has a strong impact on V-K (2mag). Conversely, a range of 2 mag in V-K corresponds to a 200K shift along the (Teff, V-K) relationship (for a fixed C/O value). Hence, the use of a (Teff, V-K) calibration established for M stars will yield large errors for S stars, so that a specific calibration must be used, as provided in the present paper. Using the atmospheric parameters derived by our method for the sample of Henize S stars, we show that the extrinsic-intrinsic dichotomy among S stars reveals itself very clearly as a bimodal distribution in the effective temperatures. Moreover, the increase of s-process element abundances with increasing C/O ratios and decreasing temperatures is apparent among intrinsic stars, confirming theoretical expectations.
- ID:
- ivo://CDS.VizieR/J/ApJS/244/12
- Title:
- A search for variable stars in M4 with K2 LCs
- Short Name:
- J/ApJS/244/12
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We extract light curves for 4554 objects with 9<G<19 in the K2 superstamp observations of the globular cluster M4, including 3784 cluster members, and search for variability. Among cluster-member objects, we detect 66 variables, of which 52 are new discoveries. Among objects not belonging to the cluster, we detect 24 variables, of which 20 are new discoveries. We additionally discover 57 cluster-member suspected variables, 10 cluster-non-member suspected variables, and four variables with ambiguous cluster membership. Our light curves reach sub-millimagnitude precision for the cluster horizontal branch, permitting us to detect asteroseismic activity in six horizontal branch stars outside the instability strip and one inside the strip but with only ~1mmag amplitude variability. Nineteen additional stars along the red giant branch also have detected asteroseismic variability. Several eclipsing binaries are found in the cluster, including a 4.6 day detached eclipsing binary and an EW-class eclipsing binary, as well as an EW with uncertain cluster membership and three other candidate EWs. A 22 day detached eclipsing binary is also found outside the cluster. We identify a candidate X-ray binary that is a cluster member with quiescent and periodic ~20mmag optical variability. We also obtain high-precision light curves for 10 of the previously known RR Lyrae variables in the cluster and identify one as a candidate Blazhko variable with a Blazhko period in excess of 78d.
- ID:
- ivo://CDS.VizieR/II/63A
- Title:
- Balmer Lines Photometric Data
- Short Name:
- II/63A
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The purpose of the catalogue is to collect the photometric determination of the Balmer line-strength. Eleven different systems, including the measurements of one or more lines, from H{alpha} to H{delta}, have been found when surveying the literature. These include alpha, beta, gamma, alpha,beta, beta,gamma, and alpha,beta,gamma from various authors. The Stroemgren H{beta} photometry is not not included in this version.
- ID:
- ivo://CDS.VizieR/J/ApJ/821/33
- Title:
- Broad H{beta} emission line in 102 Seyfert galaxies
- Short Name:
- J/ApJ/821/33
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- A sample of 102 local (0.02=<z=<0.1) Seyfert galaxies with black hole masses M_BH_>10^7^M_{sun}_ was selected from the Sloan Digital Sky Survey (SDSS) and observed using the Keck 10 m telescope to study the scaling relations between M_BH_ and host galaxy properties. We study profile changes of the broad H{beta} emission line within the three to nine year time frame between the two sets of spectra. The variability of the broad H{beta} emission line is of particular interest, not only because it is used to estimate M_BH_, but also because its strength and width are used to classify Seyfert galaxies into different types. At least some form of broad-line variability (in either width or flux) is observed in the majority (~66%) of the objects, resulting in a Seyfert-type change for ~38% of the objects, likely driven by variable accretion and/or obscuration. The broad H{beta} line virtually disappears in 3/102 (~3%) extreme cases. We discuss potential causes for these changing look active galactic nuclei. While similar dramatic transitions have previously been reported in the literature, either on a case-by-case basis or in larger samples focusing on quasars at higher redshifts, our study provides statistical information on the frequency of H{beta} line variability in a sample of low-redshift Seyfert galaxies.
- ID:
- ivo://CDS.VizieR/III/159A
- Title:
- Ca II H and K Measurements Made at MWO
- Short Name:
- III/159A
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Summaries are presented of the photoelectric measurements of stellar CaII H and K line intensity made at Mount Wilson Observatory during the years 1966-1983. These results are derived from 65,263 individual observations of 1296 stars. For each star, for each observing season, the maximum, minimum, mean, and variation of the instrumental H and K index "S" are given, as well as a measurement of the accuracy of observation. A total of 3110 seasonal summaries are reported. These observations were obtained with two instruments, HKP-1 and HKP-2. The HKP-2 instrument is a four-channel chopping spectrometer which records counts in 1.09{AA} FWHM triangular bandpasses centered in the H and K lines as well as in two 20{AA} reference bandpasses centered on 3901.067 and 4001.067{AA}. The stellar activity is expressed by the index S defined as S = {alpha} (Nh+Nk)/(Nr+Nv) where Nh and Nk are the counts (corrected from background) in the H and K lines, Nr and Nv those in the reference continuum bandpasses, and {alpha} is a constant of proportionality used to correct for night-to-night instrumental variations. Higher values of S generally correspond to higher levels of chromospehric activities. Factors which effect the ability to detect stellar activity variations and accurately measure their amplitudes such as the accuracy of the H and K measurements and scattered light contamination are discussed. Relations are given which facilitate intercomparison of "S" values with residual intensities from ordinary spectrophotometry, and for converting measurements to absolute fluxes.
- ID:
- ivo://CDS.VizieR/J/A+A/608/L8
- Title:
- Calibration of G passband for Gaia DR1
- Short Name:
- J/A+A/608/L8
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- On September 2016 the first data from Gaia were released (DR1). The first release included photometry for over 109 sources in the very broad G system. To test the correspondence between G magnitudes in DR1 and the synthetic equivalents derived using spectral energy distributions from observed and model spectrophotometry. To correct the G passband curve and to measure the zero point in the Vega system. Methods. I have computed the synthetic G and Tycho-2 BTVT photometry for a sample of stars using the Next Generation Spectral Library (NGSL) and the Hubble Space Telescope (HST) CALSPEC spectroscopic standards. I have found that the nominal G passband curve is too blue for the DR1 photometry, as shown by the presence of a color with an exponent of 0.783 eliminates the color term. The corrected passband has a Vega zero point of 0.070+/-0.004 magnitudes.
- ID:
- ivo://CDS.VizieR/III/29
- Title:
- Catalog of H{gamma} measures
- Short Name:
- III/29
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- A catalogue of equivalent widths of H{gamma} measured by R.M. Petrie in the spectra of 1171 stars is presented. The catalogue represents a compilation of all the published and unpublished values available to us. It is shown that no systematic differences exist between the equivalent widths by Petrie and those currently being derived at the Dominion Astrophysical Observatory.
- ID:
- ivo://CDS.VizieR/V/24
- Title:
- Catalogue of Geneva Photometric Boxes
- Short Name:
- V/24
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The catalogue of the Geneva photometric boxes (or Golay's boxes) is announced.
- ID:
- ivo://CDS.VizieR/J/A+A/385/867
- Title:
- CCD {Delta}a-photometry of 5 open clusters
- Short Name:
- J/A+A/385/867
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- In total, more than 550 objects within the fields of five open clusters (NGC 2439, NGC 3960, NGC 6134, NGC 6192 and NGC 6451) were investigated in order to find classical chemically peculiar stars. One bona-fide CP candidate was detected in each of the open clusters NGC 3960, NGC 6192 and NGC 6451. All three objects seem to be members of the corresponding cluster taking the results from our photometry as well as from the literature. For NGC 6192 and NGC 6451 we found widely different interstellar reddening values and therefore distances and ages in the literature. From an analysis of published Johnson UBVRI photometry, we were able to rule out a rather old age for NGC 6451. This is also supported by the finding of one peculiar object in this cluster with spectral type of about A2. Five variable objects within the field of NGC 6134 were detected. The variability exceeds 10 times (or typically 0.03 mag) the standard deviation of the weighted individual measurements. But since our observations were obtained mostly during one hour (typical integration times of five minutes per filter) on several nights within 45 days, no light curves could yet be derived. For this cluster some Am candidates were reported for which we were not able to detect a significant positive {Delta} a-value. For a description of the {Delta}a photometric system, see e.g. <GCPD/75>
