- ID:
- ivo://CDS.VizieR/J/A+A/641/A156
- Title:
- IC 4665 multi-band photometry
- Short Name:
- J/A+A/641/A156
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Debris discs orbiting young stars are key to understand dust evolution and the planetary formation process.We take advantage of a recent membership analysis of the 30Myr nearby open cluster IC 4665 based on the Gaia and DANCe surveys to revisit the disc population of this cluster. We aim to study the disc population of IC 4665 using Spitzer (MIPS and IRAC) and WISE photometry. We use several colour-colour diagrams with empirical photospheric sequences to detect the sources with an infrared excess. Independently, we also fit the spectral energy distribution (SED) of our debris disc candidates with the Virtual Observatory SED analyser (VOSA) which is capable of automatically detecting infrared excesses and provides effective temperature estimates. We find six candidates debris disc host-stars (five with MIPS and one with WISE) and two of them are new candidates. We estimate a disc fraction of 24+/-10% for the B-A stars, where our sample is expected to be complete. This is similar to what has been reported in other clusters of similar ages (Upper Centaurus Lupus, Lower Centaurus Crux, the $\beta$ Pictoris moving group, and the Pleiades). For solar type stars we find a disk fraction of 9+/-9%, lower than that observed in regions with comparable ages. Our candidates debris disc host-stars are excellent targets to be studied with ALMA or the future James Webb Space Telescope (JWST).
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Search Results
- ID:
- ivo://CDS.VizieR/J/A+A/578/A93
- Title:
- IC 342 multi-frequency radio polarization study
- Short Name:
- J/A+A/578/A93
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Magnetic fields play an important role in the formation and stabilization of spiral structures in galaxies, but the interaction between interstellar gas and magnetic fields has not yet been understood. In particular, the phenomenon of "magnetic arms" located between material arms is a mystery. The strength and structure of interstellar magnetic fields and their relation to spiral arms in gas and dust are investigated in the nearby and almost face-on spiral galaxy IC 342.
- ID:
- ivo://nasa.heasarc/ic1396ncxo
- Title:
- IC 1396N Chandra X-Ray Point Source Catalog
- Short Name:
- IC1396NCXO
- Date:
- 27 Sep 2024
- Publisher:
- NASA/GSFC HEASARC
- Description:
- The IC 1396N cometary globule (CG) within the large nearby HII region IC 1396 has been observed with the Advanced CCD Imaging Spectrometer (ACIS) detector on board the Chandra X-Ray Observatory on 2004 October 16.93 to 17.30. 117 X-ray sources are detected, of which ~ 50-60 are likely members of the young open cluster Trumpler 37 dispersed throughout the HII region, and 25 are associated with young stars formed within the globule. Infrared photometry (2MASS and Spitzer) shows that the X-ray population is very young: 3 older Class III stars, 16 classical T Tauri stars, and 6 protostars including a Class 0/I system. The authors infer a total T Tauri population of ~ 30 stars in the globule, including the undetected population, with a star formation efficiency of 1%-4%. An elongated source spatial distribution with an age gradient oriented toward the exciting star is discovered in the X-ray population of IC 1396N, supporting similar findings in other cometary globules. The geometric and age distribution is consistent with the radiation-driven implosion (RDI) model for triggered star formation in CGs by H II region shocks. The authors include only results arising from the imaging array (ACIS-I) of four abutted 1024 x 1024 pixel front-side illuminated CCDs covering about 17' x 17' on the sky. The aim point of the array was R.A. = 21h40m42.4s, Dec. = +58d1609.7" (J2000.0) or (l,b) = (100.0, + 4.2), and the satellite roll angle (i.e., orientation of the CCD array relative to the north-south direction) was 245.9 degrees. The total net exposure time of the observation is 30 ks with no background flaring due to solar activity or data losses. This table was created by the HEASARC in February 2009 based on the electronic version of Tables 1 and 2 from the paper which were obtained from the CDS (their catalog J/ApJ/654/316 files table1.dat and table2.dat). This is a service provided by NASA HEASARC .
6754. Ic photometry of IC 348
- ID:
- ivo://CDS.VizieR/J/MNRAS/358/341
- Title:
- Ic photometry of IC 348
- Short Name:
- J/MNRAS/358/341
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a photometric study of I-band variability in the young cluster IC 348. The main purpose of the study was to identify periodic stars. In all, we find 50 periodic stars, of which 32 were previously unknown. For the first time in IC 348, we discover periods in significant numbers of lower-mass stars (M<0.25M_{sun}_) and classical T Tauri stars.
- ID:
- ivo://CDS.VizieR/J/A+AS/137/305
- Title:
- IC 348 proper motion catalogue
- Short Name:
- J/A+AS/137/305
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- A new proper motion study for about 1400 stars with R<18mag in a one square degree region around the young open cluster IC 348 based on Schmidt plates is presented. With an overall accuracy of about 3mas/yr (2.5mas/yr, respectively for all stars with R<17mag) we have obtained membership probabilities dividing our sample into three groups: foreground stars, cluster stars and background stars. This separation is also supported by the proper motion distribution with respect to the direction of the standard antapex and an increase of mean proper motion cluster membership probabilities with smaller cluster radii. 240 stars of our sample have cluster membership probabilities larger than 80%.
- ID:
- ivo://CDS.VizieR/J/ApJ/873/132
- Title:
- ICRF3 radio-loud quasars with Gaia DR2 data
- Short Name:
- J/ApJ/873/132
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We investigate a sample of 3413 International Celestial Reference Frame (ICRF3) extragalactic radio-loud sources with accurate positions determined by very long baseline interferometry in the S/X band, mostly active galactic nuclei and quasars, which are cross-matched with optical sources in the second Gaia data release (Gaia DR2). The main goal of this study is to determine a core sample of astrometric objects that define the mutual orientation of the two fundamental reference frames, the Gaia (optical) and the ICRF3 (radio) frames. The distribution of normalized offsets between the VLBI sources and their optical counterparts is non-Rayleigh, with a deficit around the modal value and a tail extending beyond the 3{sigma} confidence level. A few filters are applied to the sample in order to discard double cross-matches, confusion sources, and Gaia astrometric solutions of doubtful quality. Panoramic Survey Telescope and Rapid Response System and Dark Energy Survey stacked multicolor images are used to further deselect objects that are less suitable for precision astrometry, such as extended galaxies, double and multiple sources, and obvious misidentifications. After this cleaning, 2643 quasars remain, of which 20% still have normalized offset magnitudes exceeding 3, or a 99% confidence level. We publish a list of 2119 radio-loud quasars of prime astrometric quality. The observed dependence of binned median offset on redshift shows the expected decline at small redshifts, but also an unexpected rise at z~1.6, which may be attributed to the emergence of the CIV emission line in the Gaia's G band. The Gaia DR2 parallax zero-point is found to be color-dependent, suggesting an uncorrected instrumental calibration effect.
- ID:
- ivo://CDS.VizieR/J/MNRAS/430/2797
- Title:
- ICRF2 sources of the Rio survey
- Short Name:
- J/MNRAS/430/2797
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We obtained improved optical positions for 300 ICRF2 sources - the Rio survey. We compared the Rio survey with 10 other selected optical astrometric surveys and studied the link between the Hipparcos Catalogue Reference Frame (HCRF) and the International Celestial Reference Frame, Second Realization (ICRF2). We investigated the possible causes for the observed non-coincidence between the optical and ICRF2 positions. The Rio survey positions were referred to the second version of the United States Naval Observatory CCD Astrograph Catalog (UCAC2), currently the best tested HCRF densification. The sources are between -90{deg}<{delta}<+30{deg}. We used two telescopes with suitable diameters and focal lengths to properly link the observed ICRF2 sources with the UCAC2, using intermediate brightness stars. We certified the astrometry done with many statistical tests. The average 'optical minus ICRF2' offsets and respective standard deviations in ({alpha}, {delta}) were -3mas (41mas) and +4 (45mas). The Rio survey represents well the zero-point offset of the other surveys. The standard error of 3.5mas found for the HCRF/ICRF2 link indicates an error excess that can be originated by a non-coincidence between the observed optical/VLBI positions. We thus discussed the influence of the errors from the UCAC2. Then, we searched for correlations with the source morphology, represented by structure indices defined in the radio and in the optical domain. Finally, we studied how the position offsets could originate from the perturbation of the optical point spread function (PSF) of the source's core, by a second source of flux. We found an analytical relation that describes the resulting centroid shift, as a function of the atmospheric seeing, the brightness ratio and the relative distance between the two contributing flux sources. Two scenarios, modelled by this relation, are discussed: an extinction window in the dust torus nearby the core, and a Galactic star near the line of sight.
- ID:
- ivo://CDS.VizieR/J/other/KFNT/27.299
- Title:
- ICRF stars near extragalactic radio sources
- Short Name:
- J/other/KFNT/27.
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The compiled catalogue of 231044 stars was created from photographic and CCD observations of position catalogues observed by ground based telescopes. The catalogue destine for optical observations VLBI-ICRS astrometrical extragalactic radiosources (ERS) with telescopes equiped with CCD-cameras. The main purpose of this catalogue is to ensure the reference stars in optics for reducing positions of faint astrometrical ERS 17-22mag relative to more bright reference stars 14-17mag. The catalogue contains 231044 star positions in fields 40'x40' near 240 ERS. More than nine catalogues of stars coordinates were used for compiling the Pul-ERS catalogue. For 69% of stars the proper motions were taken from UCAC3 catalogue to convert the position stars to the common epoch. The number of position measurements for each star varies from one to more than ten records. The inner precision of positions of stars in Pul-ERS is from 4 to 150mas. 159331 stars of the compiled catalogue were identified with stars of the UCAC3. The average internal accuracy of positions on both coordinates is not worse 0.11".
6759. IC 4651 uvby photometry
- ID:
- ivo://CDS.VizieR/J/A+A/361/929
- Title:
- IC 4651 uvby photometry
- Short Name:
- J/A+A/361/929
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- New accurate CCD photometry in the u, v, b and y bands of the Stroemgren system filters has been obtained for 17640 stars to approximately. V=20mag in a approximately 21' x 21' field centered on the intermediate-age open cluster IC 4651. The observations was obtained with the Danish 1.5-m telescope at the European Southern Observatory, La Silla, Chile. Table 1 contains information about the Date, Night, Filter, Exposure time, Airmass, CCD rotation angle, and RA- , DE-offsets for all 89 frames. Table 2 gives cross-references between the MEI-system (this paper) and the Lindoff (1972A&AS....7..231L, IC 4651 NNN), Eggen (1971ApJ...166...87E, Cl* IC 4651 Egg NN), Anthony-Twarog & Twarog (1987AJ.....94.1222A, Cl* IC 4651 AT 1-NNN, Cl* IC 4651 AT 2-NN), and Anthony-Twarog et al. (1988AJ.....95.1453A, Cl* IC 4651 AMC I-NNN, Cl* IC 4651 AMC NNNN) identification numbers. Table 3 is the final catalogue of the new Stroemgren uvby photometry, ordered by MEI identification number. For each star, it gives the MEI number, Global CCD x- and y-coordinates, J2000 coordinates , the new y, b, v, and u magnitudes on the standard system, number of detections of the individual stars, and their mean errors.
- ID:
- ivo://CDS.VizieR/J/A+A/623/A22
- Title:
- IC 4996 Vilnius phot. and Gaia DR2 astrometry
- Short Name:
- J/A+A/623/A22
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The open cluster IC 4996 in Cygnus and its vicinity are investigated applying two-dimensional photometric classification of stars measured in the Vilnius seven-color photometric system. Cluster members are identified by applying distances based on the Gaia DR2 parallaxes and the point vector diagram of the Gaia DR2 proper motions. For some B-type stars, spectroscopic MK types are also obtained from the Asiago spectra and collected from the literature. New parameters of the cluster are derived. Th interstellar extinction A(v) covers a wide range of values, from 1.3 to 2.4mag, the mean value in the central part of the cluster is 1.8mag. The cluster distance is 1915+/-110pc, and its age is within 8-10Myr. The cluster exhibits a long sequence from early B to G stars, where stars cooler than B8 are in the pre-main-sequence stage. The plot of the extinction versus distance shows a steep rise of A(v) up to 1.6mag at 700-800pc, which is probably related to dust clouds at the edge of the Great Cygnus Rift. The next extinction rise by an additional 0.8 mag at d>=1.7kpc is probably related to the associations Cyg OB1 and Cyg OB3. The cluster IC 4996 does not belong to the Cyg OB1 association, which is located closer to the Sun, at 1682+/-116pc. It seems likely that the cluster and the surrounding O-B stars have a common origin with the nearby association Cyg OB3 since the Gaia data show that these stellar groups are located at a similar distance.