- ID:
- ivo://CDS.VizieR/J/AJ/155/116
- Title:
- The globular cluster M14.II. Variable stars
- Short Name:
- J/AJ/155/116
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present time-series BVI photometry for the Galactic globular cluster NGC 6402 (M14). The data consist of ~137 images per filter, obtained using the 0.9 and 1.0 m SMARTS telescopes at the Cerro Tololo Inter-American Observatory. The images were obtained during two observing runs in 2006-2007. The image-subtraction package ISIS, along with DAOPHOT II/ALLFRAME, was used to perform crowded-field photometry and search for variable stars. We identified 130 variables, eight of which are new discoveries. The variable star population is comprised of 56 ab-type RR Lyrae stars, 54 c-type RR Lyrae, 6 type II Cepheids, 1 W UMa star, 1 detached eclipsing binary, and 12 long-period variables. We provide Fourier decomposition parameters for the RR Lyrae, and discuss the physical parameters and photometric metallicity derived therefrom. The M14 distance modulus is also discussed, based on different approaches for the calibration of the absolute magnitudes of RR Lyrae stars. The possible presence of second-overtone RR Lyrae in M14 is critically addressed, with our results arguing against this possibility. By considering all of the RR Lyrae stars as members of the cluster, we derive <P_ab_>=0.589 days. This, together with the position of the RR Lyrae stars of both Bailey types in the period-amplitude diagram, suggests an Oosterhoff-intermediate classification for the cluster. Such an intermediate Oosterhoff type is much more commonly found in nearby extragalactic systems, and we critically discuss several other possible indications that may point to an extragalactic origin for this cluster.
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Search Results
- ID:
- ivo://CDS.VizieR/J/ApJS/224/5
- Title:
- The Herschel Orion Protostar Survey (HOPS): SEDs
- Short Name:
- J/ApJS/224/5
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present key results from the Herschel Orion Protostar Survey (HOPS): spectral energy distributions (SEDs) and model fits of 330 young stellar objects, predominantly protostars, in the Orion molecular clouds. This is the largest sample of protostars studied in a single, nearby star formation complex. With near-infrared photometry from 2MASS, mid- and far-infrared data from Spitzer and Herschel, and submillimeter photometry from APEX, our SEDs cover 1.2-870{mu}m and sample the peak of the protostellar envelope emission at ~100{mu}m. Using mid-IR spectral indices and bolometric temperatures, we classify our sample into 92 Class 0 protostars, 125 Class I protostars, 102 flat-spectrum sources, and 11 Class II pre-main-sequence stars. We implement a simple protostellar model (including a disk in an infalling envelope with outflow cavities) to generate a grid of 30400 model SEDs and use it to determine the best-fit model parameters for each protostar. We argue that far-IR data are essential for accurate constraints on protostellar envelope properties. We find that most protostars, and in particular the flat-spectrum sources, are well fit. The median envelope density and median inclination angle decrease from Class 0 to Class I to flat-spectrum protostars, despite the broad range in best-fit parameters in each of the three categories. We also discuss degeneracies in our model parameters. Our results confirm that the different protostellar classes generally correspond to an evolutionary sequence with a decreasing envelope infall rate, but the inclination angle also plays a role in the appearance, and thus interpretation, of the SEDs.
- ID:
- ivo://CDS.VizieR/J/MNRAS/419/3505
- Title:
- The HeViCS Bright Galaxy Sample
- Short Name:
- J/MNRAS/419/3505
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We describe the Herschel Virgo Cluster Survey and the first data that cover the complete survey area (four 4x4deg^2^ regions). We use these data to measure and compare the global far-infrared properties of 78 optically bright galaxies that are selected at 500um and detected in all five far-infrared bands. We show that our measurements and calibration are broadly consistent with previous data obtained by the IRAS, ISO, Spitzer and Planck. We use SPIRE and PACS photometry data to produce 100-, 160-, 250-, 350- and 500-um cluster luminosity distributions.
- ID:
- ivo://CDS.VizieR/J/AJ/156/186
- Title:
- The High Cadence Transit Survey (HiTS)
- Short Name:
- J/AJ/156/186
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The High Cadence Transient Survey (HiTS) aims to discover and study transient objects with characteristic timescales between hours and days, such as pulsating, eclipsing, and exploding stars. This survey represents a unique laboratory to explore large etendue observations from cadences of about 0.1 days and test new computational tools for the analysis of large data. This work follows a fully data science approach, from the raw data to the analysis and classification of variable sources. We compile a catalog of ~15 million object detections and a catalog of ~2.5 million light curves classified by variability. The typical depth of the survey is 24.2, 24.3, 24.1, and 23.8 in the u, g, r, and i bands, respectively. We classified all point-like nonmoving sources by first extracting features from their light curves and then applying a random forest classifier. For the classification, we used a training set constructed using a combination of cross-matched catalogs, visual inspection, transfer/active learning, and data augmentation. The classification model consists of several random forest classifiers organized in a hierarchical scheme. The classifier accuracy estimated on a test set is approximately 97%. In the unlabeled data, 3485 sources were classified as variables, of which 1321 were classified as periodic. Among the periodic classes, we discovered with high confidence one {delta} Scuti, 39 eclipsing binaries, 48 rotational variables, and 90 RR Lyrae, and for the nonperiodic classes, we discovered one cataclysmic variable, 630 QSOs, and one supernova candidate.
- ID:
- ivo://CDS.VizieR/J/ApJ/844/78
- Title:
- The high-redshift COBRA survey: IRAC obs.
- Short Name:
- J/ApJ/844/78
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present 190 galaxy cluster candidates (most at high redshift) based on galaxy overdensity measurements in the Spitzer/IRAC imaging of the fields surrounding 646 bent, double-lobed radio sources drawn from the Clusters Occupied by Bent Radio AGN (COBRA) Survey. The COBRA sources were chosen as objects in the Very Large Array FIRST survey that lack optical counterparts in the Sloan Digital Sky Survey to a limit of m_r_=22, making them likely to lie at high redshift. This is confirmed by our observations: the redshift distribution of COBRA sources with estimated redshifts peaks near z=1 and extends out to z~3. Cluster candidates were identified by comparing our target fields to a background field and searching for statistically significant (>=2{sigma}) excesses in the galaxy number counts surrounding the radio sources; 190 fields satisfy the >=2{sigma} limit. We find that 530 fields (82.0%) have a net positive excess of galaxies surrounding the radio source. Many of the fields with positive excesses but below the 2{sigma} cutoff are likely to be galaxy groups. Forty-one COBRA sources are quasars with known spectroscopic redshifts, which may be tracers of some of the most distant clusters known.
- ID:
- ivo://CDS.VizieR/J/ApJ/864/40
- Title:
- The HIPASS Catalog (HICAT) + WISE galaxies
- Short Name:
- J/ApJ/864/40
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We have measured the relationships between HI mass, stellar mass, and star formation rate using the HI Parkes All-Sky Survey Catalog (HICAT) and the Wide-field Infrared Survey Explorer (WISE). Of the 3513 HICAT sources, we find 3.4{mu}m counterparts for 2896 sources (80%), and provide new WISE-matched aperture photometry for these galaxies. For our principal sample of spiral galaxies with W1<=10mag and z<=0.01, we identify HI detections for 93% of the sample. We measure lower HI-stellar mass relationships for HI-selected samples that do not include spiral galaxies with little HI gas. Our observations of the spiral sample show that HI mass increases with stellar mass with a power-law index of 0.35; however, this value is dependent on T-type, which affects both the median and the dispersion of HI mass. We also observe an upper limit on the HI gas fraction, which is consistent with a halo spin parameter model. We measure the star formation efficiency of spiral galaxies to be constant at 10^-9.57^yr^-1^+/-0.4dex for 2.5 orders of magnitude in stellar mass, despite the higher stellar mass spiral showing evidence of quenched star formation.
- ID:
- ivo://CDS.VizieR/J/A+A/544/A9
- Title:
- The International Deep Planet Survey. I.
- Short Name:
- J/A+A/544/A9
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Breakthrough direct detections of planetary companions orbiting A-type stars confirm the existence of massive planets at relatively large separations, but dedicated surveys are required to estimate the frequency of similar planetary systems. To measure the first estimation of the giant exoplanetary systems frequency at large orbital separation around A-stars, we have conducted a deep-imaging survey of young (8-400Myr), nearby (19-84pc) A- and F-stars to search for substellar companions in the ~10-300AU range. The sample of 42 stars combines all A-stars observed in previous AO planet search surveys reported in the literature with new AO observations from VLT/NaCo and Gemini/NIRI. It represents an initial subset of the International Deep Planet Survey (IDPS) sample of stars covering M- to B-stars. The data were obtained with diffraction-limited observations in H- and Ks-band combined with angular differential imaging to suppress the speckle noise of the central stars, resulting in typical 5-sigma detection limits in magnitude difference of 12mag at 1", 14mag at 2" and 16mag at 5" which is sufficient to detect massive planets. A detailed statistical analysis of the survey results is performed using Monte Carlo simulations. Considering the planet detections, we estimate the fraction of A-stars having at least one massive planet (3-14M_Jup_) in the range 5-320AU to be inside 5.9-18.8% at 68% confidence, assuming a flat distribution for the mass of the planets. By comparison, the brown dwarf (15-75M_Jup_) frequency for the sample is 2.0-8.9% at 68% confidence in the range 5-320AU. Assuming power law distributions for the mass and semimajor axis of the planet population, the AO data are consistent with a declining number of massive planets with increasing orbital radius which is distinct from the rising slope inferred from radial velocity (RV) surveys around evolved A-stars and suggests that the peak of the massive planet population around A-stars may occur at separations between the ranges probed by existing RV and AO observations. Finally, we report the discovery of three new close M-star companions to HIP 104365 and HIP 42334.
- ID:
- ivo://CDS.VizieR/J/A+A/587/A121
- Title:
- The IR source catalog of nearby galaxies
- Short Name:
- J/A+A/587/A121
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- To complement the study of transient phenomena and to assist subsequent observations in the mid-infrared, we extract point source photometry from archival mosaics of nearby galaxies with high star formation rates within 4 Mpc. Point spread function photometry was performed on sources detected in both Spitzer IRAC 3.6um and 4.5um bands at greater than 3{sigma} above background. These data were then supplemented by aperture photometry in the IRAC 5.8um and 8.0um bands conducted at the positions of the shorter wavelength sources. For sources with no detected object in the longer wavelengths, we estimated magnitude limits based on the local sky background.
- ID:
- ivo://CDS.VizieR/J/A+A/400/903
- Title:
- The ISOGAL field FC-01863+00035
- Short Name:
- J/A+A/400/903
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- A 0.35x0.29{deg} field centered at l=-18.63{deg}, b=0.35{deg} was observed during the ISOGAL survey by ISOCAM imaging at 7{mu}m and 15{mu}m. 648 objects were detected and their brightness are measured. By combining with the DENIS data in the near-infrared J and Ks bands, one derives the extinction at 7{mu}m through A_Ks_-A_7_=0.35(A_J_-A_Ks_) which yields A_7_/Av~0.03 from the near-IR extinction values of van de Hulst-Glass (Glass, 1999MNRAS.308..127G). The extinction structure along the line of sight is then determined from the values of J-Ks or Ks-[7] of the ISOGAL sources identified as RGB or early AGB stars with mild mass-loss. The distribution of Av ranges from 0 to ~45 and it reflects the concentration of the extinction in the spiral arms. Based on their locations in color-magnitude diagrams and a few cross-identifications with IRAS and MSX sources, the nature of objects is discussed in comparison with the case of a low extinction field in Baade's Window. Most of the objects are either AGB stars with moderate mass loss rate or luminous RGB stars. Some of them may be AGB stars with high mass loss rate. In addition, a few young stellar objects (YSOs) are present.
- ID:
- ivo://CDS.VizieR/II/243
- Title:
- The ISOGAL Point Source Catalogue - IGPSC
- Short Name:
- II/243
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The ISOGAL survey is one of the largest imaging programme performed by the ISO satellite. About 16deg^2^ mainly distributed in the inner Galactic disk were mapped at 7 and/or 15 micron ({mu}m). Because of highly structured background and high source density, a special point source extraction algorithm was used and resulted in a 100000 point source catalogue. The mid-infrared data have been associated with near-infrared DENIS sources, providing an up to five wavelength photometric catalogue with a typical astrometric accuracy better than 1 arcsecond. The point source catalogue contains the positional and photometric parameters of all ISOGAL sources, together with various quality flags aimed at giving an estimate of the reliability of the detections and of the associations between the different bands (see the paper for a complete description).
