- ID:
- ivo://CDS.VizieR/J/AJ/159/198
- Title:
- Cataclysmic variables in the ZTF 1st-yr (2018-2019)
- Short Name:
- J/AJ/159/198
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Using selection criteria based on amplitude, time, and color, we have identified 329 objects as known or candidate cataclysmic variables (CVs) during the first year of testing and operation of the Zwicky Transient Facility. Of these, 90 are previously confirmed CVs, 218 are strong candidates based on the shape and color of their light curves obtained during 3-562days of observation, and the remaining 21 are possible CVs but with too few data points to be listed as good candidates. Almost half of the strong candidates are within 10{deg} of the galactic plane, in contrast to most other large surveys that have avoided crowded fields. The available Gaia parallaxes are consistent with sampling the low mass transfer CVs, as predicted by population models. Our follow-up spectra have confirmed Balmer/helium emission lines in 27 objects, with four showing high-excitation HeII emission, including candidates for an AM CVn, a polar, and an intermediate polar. Our results demonstrate that a complete survey of the Galactic plane is needed to accomplish an accurate determination of the number of CVs existing in the Milky Way.
Number of results to display per page
Search Results
- ID:
- ivo://CDS.VizieR/III/164
- Title:
- Catalog of Eq.Widths of Interstellar 217nm Band
- Short Name:
- III/164
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- (from CDS Inf. Bull. 40, 31) The main task of the catalogue consists in a comprehensive collection of equivalent widths of the 217nm band derived from both spectrophotometric and filterphotometric measurements obtained with TD-1, OAO-2 and ANS satellites. These data concern reddened O, B stars with color excesses E(B-V) >= 0.02 mag. The extinction curve is approximated by the empirical formula introduced by Guertler et al. (1982AN....303..105G) e({lambda}) = A(i/{lambda} - 1/{lambda}o)^n^ + B + C {kappa}({lambda}) The relative errors amount to about {delta}A/A = +/- 0.10, {delta}B/B = +/- 0.02 and {delta}C/C = +/- 0.03.
- ID:
- ivo://CDS.VizieR/J/ApJS/181/605
- Title:
- Catalog of X-ray sources in NGC 4278
- Short Name:
- J/ApJS/181/605
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the properties of the discrete X-ray sources detected in our monitoring program of the globular cluster (GC) rich elliptical galaxy, NGC 4278, observed with Chandra ACIS-S in six separate pointings, resulting in a co-added exposure of 458ks. From this deep observation, 236 sources have been detected within the region overlapped by all observations, 180 of which lie within the D25 ellipse of the galaxy. These 236 sources range in L_X_ from 3.5x10^36^erg/s (with 3{sigma} upper limit <=1x10^37^erg/s) to ~2x10^40^erg/s, including the central nuclear source which has been classified as a LINER. From optical data, 39 X-ray sources have been determined to be coincident with a GC, these sources tend to have high X-ray luminosity, with 10 of these sources exhibiting L_X_>1x10^38^erg/s. From X-ray source photometry, it has been determined that the majority of the 236 point sources that have well-constrained colors have values that are consistent with typical low-mass X-ray binary spectra, with 29 of these sources expected to be background objects from the log N-log S relation. There are 103 sources in this population that exhibit long-term variability, indicating that they are accreting compact objects. Three of these sources have been identified as transient candidates, with a further three possible transients. Spectral variations have also been identified in the majority of the source population, where a diverse range of variability has been identified, indicating that there are many different source classes located within this galaxy.
- ID:
- ivo://CDS.VizieR/J/MNRAS/426/1475
- Title:
- CaT in 903 globular clusters
- Short Name:
- J/MNRAS/426/1475
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Although the colour distribution of globular clusters in massive galaxies is well known to be bimodal, the spectroscopic metallicity distribution has been measured in only a few galaxies. After redefining the calcium triplet index-metallicity relation, we use our relation to derive the metallicity of 903 globular clusters in 11 early-type galaxies. This is the largest sample of spectroscopic globular cluster metallicities yet assembled. We compare these metallicities with those derived from Lick indices finding good agreement. In six of the eight galaxies with sufficient numbers of high-quality spectra we find bimodality in the spectroscopic metallicity distribution. Our results imply that most massive early-type galaxies have bimodal metallicity as well as colour distributions. This bimodality suggests that most massive early-type galaxies experienced two periods of star formation.
- ID:
- ivo://CDS.VizieR/J/ApJ/880/7
- Title:
- Census of the Local Universe survey. I. CLU-Halpha
- Short Name:
- J/ApJ/880/7
- Date:
- 03 Nov 2021 07:51:08
- Publisher:
- CDS
- Description:
- We present the Census of the Local Universe (CLU) narrowband survey to search for emission-line (H{alpha}) galaxies. CLU-H{alpha} has imaged ~3{pi} of the sky (26470deg^2^) with four narrowband filters that probe a distance out to 200Mpc. We have obtained spectroscopic follow-up for galaxy candidates in 14 preliminary fields (101.6deg^2^) to characterize the limits and completeness of the survey. In these preliminary fields, CLU can identify emission lines down to an H{alpha} flux limit of 10^-14^erg/s/cm^2^ at 90% completeness, and recovers 83% (67%) of the H{alpha} flux from cataloged galaxies in our search volume at the {Sigma}=2.5 ({Sigma}=5) color excess levels. The contamination from galaxies with no emission lines is 61% (12%) for {Sigma}=2.5 ({Sigma}=5). Also, in the regions of overlap between our preliminary fields and previous emission-line surveys, we recover the majority of the galaxies found in previous surveys and identify an additional ~300 galaxies. In total, we find 90 galaxies with no previous distance information, several of which are interesting objects: 7 blue compact dwarfs, 1 green pea, and a Seyfert galaxy; we also identify a known planetary nebula. These objects show that the CLU-H{alpha} survey can be a discovery machine for objects in our own Galaxy and extreme galaxies out to intermediate redshifts. However, the majority of the CLU-H{alpha} galaxies identified in this work show properties consistent with normal star-forming galaxies. CLU-H{alpha} galaxies with new redshifts will be added to existing galaxy catalogs to focus the search for the electromagnetic counterpart to gravitational wave events.
- ID:
- ivo://CDS.VizieR/J/AJ/131/1236
- Title:
- Central black holes of spiral galaxies
- Short Name:
- J/AJ/131/1236
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Central black hole masses for 117 spiral galaxies representing morphological stages S0/a through Sc and taken from the large spectroscopic survey of Ho et al. (Cat. <J/ApJS/112/315>) are derived using Ks-band data from the Two Micron All Sky Survey. Black hole masses are found using a calibrated black hole-Ks bulge luminosity relation, while bulge luminosities are measured by means of a two-dimensional bulge-disk decomposition routine.
- ID:
- ivo://CDS.VizieR/J/A+A/618/A122
- Title:
- Cetus dSph stellar chemo-kinematics
- Short Name:
- J/A+A/618/A122
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Cetus is an isolated, dwarf spheroidal (dSph) galaxy at a distance of 755kpc. In order to quantify its stellar chemo-kinematical properties, we observed individual red giants branch stars in Cetus with the Very Large Telescope (VLT) FORS2 instrument, in Mask eXchange Unit (MXU) configuration. The kinematic analysis shows that Cetus is a mainly pressure-supported ({sigma}_v_=11.0^+1.6^_-1.3_km/s), dark-matter-dominated system (M_1/2_/L_V_=23.9^+9.7^_-8.9_M_{sun}_/L_{sun}_) with no significant signs of internal rotation. We find Cetus to be a metal-poor system with a significant metallicity spread (median [Fe/H]=-1.71dex, median-absolute-deviation =0.49dex), as expected for its stellar mass. We report the presence of a mild metallicity gradient compatible with those found in other dSphs of the same luminosity; we trace the presence of a stellar population gradient also in the spatial distribution of stars in different evolutionary phases in ancillary photometric data. There are tentative indications of two chemo-kinematically distinct sub-populations, with the more metal-poor stars showing a hotter kinematics than the metal-richer ones. Our results add Cetus to the growing scatter in stellar-dark matter halo properties in low-mass galactic systems. The presence of a metallicity gradient akin to those found in similar systems inhabiting different environments may hint at metallicity gradients in Local Group early-type dwarfs being driven by internal mechanisms.
48. CF-HiZELS survey
- ID:
- ivo://CDS.VizieR/J/MNRAS/451/2303
- Title:
- CF-HiZELS survey
- Short Name:
- J/MNRAS/451/2303
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present results from the largest contiguous narrow-band survey in the near-infrared. We have used the wide-field infrared camera/Canada-France-Hawaii Telescope and the lowOH2 filter (1.187+/-0.005{mu}m) to survey ~10deg^2^ of contiguous extragalactic sky in the SA22 field. A total of ~6000 candidate emission-line galaxies are found. We use deep ugrizJK data to obtain robust photometric redshifts. We combine our data with the High-redshift(Z) Emission Line Survey (HiZELS), explore spectroscopic surveys (VVDS, VIPERS) and obtain our own spectroscopic follow-up with KMOS, FMOS and MOSFIRE to derive large samples of high-redshift emission-line selected galaxies: 3471 H{alpha} emitters at z=0.8, 1343 [OIII] + H{beta} emitters at z=1.4 and 572 [OII] emitters at z=2.2. We probe comoving volumes of >10^6^Mpc^3^ and find significant overdensities, including an 8.5{sigma} (spectroscopically confirmed) overdensity of H{alpha} emitters at z=0.81. We derive H{alpha}, [OIII] + H{beta} and [OII] luminosity functions at z=0.8, 1.4, 2.2, respectively, and present implications for future surveys such as Euclid. Our uniquely large volumes/areas allow us to subdivide the samples in thousands of randomized combinations of areas and provide a robust empirical measurement of sample/cosmic variance. We show that surveys for star-forming/emission-line galaxies at a depth similar to ours can only overcome cosmic-variance (errors <10 percent) if they are based on volumes >5x10^5^Mpc^3^; errors on L* and {phi}* due to sample (cosmic) variance on surveys probing ~10^4^ and ~10^5^Mpc^3^ are typically very high: ~300 and ~40-60 percent, respectively.
- ID:
- ivo://CDS.VizieR/J/ApJ/481/49
- Title:
- CFRS XIV. Field galaxies up to z=1
- Short Name:
- J/ApJ/481/49
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The spectral properties of more than 400 Canada-France Redshift Survey (CFRS) galaxies and their changes over the redshift interval 0<=z<=1.3 are investigated. Emission-line intensities and equivalent widths for accessible lines have been measured, as well as continuum color indices based on 200{AA} wide spectral regions.
- ID:
- ivo://CDS.VizieR/J/ApJS/178/339
- Title:
- ChaMP extended stellar survey (ChESS)
- Short Name:
- J/ApJS/178/339
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present 348 X-ray-emitting stars identified from correlating the Extended Chandra Multiwavelength Project (ChaMP), a wide-area serendipitous survey based on archival X-ray images, with the Sloan Digital Sky Survey (SDSS-DR6). We use morphological star/galaxy separation, matching to an SDSS quasar catalog, an optical color-magnitude cut, and X-ray data-quality tests to create our catalog, the ChaMP Extended Stellar Survey (ChESS), from a sample of 2121 matched ChaMP/SDSS sources. Our cuts retain 92% of the spectroscopically confirmed stars in the original sample while excluding 99.6% of the 684 spectroscopically confirmed extragalactic sources. Fewer than 3% of the sources in our final catalog are previously identified stellar X-ray emitters. For 42 catalog members, spectroscopic classifications are available in the literature. We present new spectral classifications and H{alpha} measurements for an additional 79 stars. The catalog is dominated by main-sequence stars; we estimate the fraction of giants in ChESS is ~10%. We identify seven giant stars (including a possible Cepheid and an RR Lyrae star) as ChaMP sources, as well as three cataclysmic variables. Future papers will present analyses of source variability and comparisons of this catalog to models of stellar activity in the Galactic disk.