- ID:
- ivo://CDS.VizieR/J/A+A/450/147
- Title:
- IzJHKs photometry of Collinder 359
- Short Name:
- J/A+A/450/147
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the first deep, optical, wide-field imaging survey of the young open cluster Collinder 359, complemented by near-infrared follow-up observations. This study is part of a large programme aimed at examining the dependence of the mass function on environment and time. We have surveyed 1.6 square degrees in the cluster, in the I and z filters, with the CFH12K camera on the Canada-France-Hawaii 3.6-m telescope down to completeness and detection limits in both filters of 22.0 and 24.0mag, respectively. Based on their location in the optical (I-z,I) colour-magnitude diagram, we have extracted new cluster member candidates in Collinder 359 spanning 1.3-0.03M_{sun}_, assuming an age of 60Myr and a distance of 450pc for the cluster. We have used the 2MASS database as well as our own near-infrared photometry to examine the membership status of the optically-selected cluster candidates. Comparison of the location of the most massive members in Collinder 359 in a (B-V,V) diagram with theoretical isochrones suggests that Collinder 359 is older than Alpha Per but younger than the Pleiades. We discuss the possible relationship between Collinder 359 and IC 4665 as both clusters harbour similar parameters, including proper motion, distance, and age.
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Search Results
- ID:
- ivo://CDS.VizieR/J/A+A/522/A112
- Title:
- i'z' photometry of L5 and later dwarf candidates
- Short Name:
- J/A+A/522/A112
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Thanks to recent and ongoing large scale surveys, hundreds of brown dwarfs have been discovered in the last decade. The Canada-France Brown Dwarf Survey is a wide-field survey for cool brown dwarfs conducted with the MegaCam camera on the Canada-France-Hawaii Telescope. Our objectives are to find ultracool brown dwarfs and to constrain the field brown-dwarf luminosity function and the mass function from a large and homogeneous sample of L and T dwarfs. We identify candidates in CFHT/MegaCam i' and z' images and follow them up with pointed near infrared (NIR) imaging on several telescopes. Halfway through our survey we found ~50 T dwarfs and ~170 L or ultra cool M dwarfs drawn from a larger sample of 1400 candidates with typical ultracool dwarfs i'-z' colours, found in 780 square degrees.
- ID:
- ivo://CDS.VizieR/J/A+A/400/891
- Title:
- IZ photometry of Pleiades brown dwarfs
- Short Name:
- J/A+A/400/891
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the results of a 6.4 square degrees imaging survey of the Pleiades cluster in the I and Z-bands. The survey extends up to 3{deg} from the cluster center and is 90% complete down to I~=22. It covers a mass range from 0.03M_{sun}_ to 0.48M_{sun}_ and yields 40 brown dwarf candidates (BDCs) of which 29 are new. The spatial distribution of BDCs is fitted by a King profile in order to estimate the cluster substellar core radius. The Pleiades mass function is then derived across the stellar-substellar boundary and we find that, between 0.03M_{sun}_ and 0.48M_{sun}_, it is well represented by a single power-law, dN/dM{prop.to}M^-{alpha}^, with an index alpha=0.60+/-0.11. Over a larger mass domain, however, from 0.03M_{sun}_ to 10M_{sun}_, the mass function is better fitted by a log-normal function. We estimate that brown dwarfs represent about 25% of the cluster population which nevertheless makes up less than 1.5% of the cluster mass. The early dynamical evolution of the cluster appears to have had little effect on its present mass distribution at an age of 120Myr. Comparison between the Pleiades mass function and the Galactic field mass function suggests that apparent differences may be mostly due to unresolved binary systems.
- ID:
- ivo://CDS.VizieR/J/A+A/643/A113
- Title:
- iz photometry of S190814bv ctp candidates
- Short Name:
- J/A+A/643/A113
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Gravitational wave (GW) astronomy has rapidly reached maturity, becoming a fundamental observing window for modern astrophysics. The coalescences of a few tens of black hole (BH) binaries have been detected, while the number of events possibly including a neutron star (NS) is still limited to a few. On 2019 August 14, the LIGO and Virgo interferometers detected a high-significance event labelled S190814bv. A preliminary analysis of the GW data suggests that the event was likely due to the merger of a compact binary system formed by a BH and a NS. In this paper, we present our extensive search campaign aimed at uncovering the potential optical and near infrared electromagnetic counterpart of S190814bv. We found no convincing electromagnetic counterpart in our data. We therefore use our non-detection to place limits on the properties of the putative outflows that could have been produced by the binary during and after the merger. Thanks to the three-detector observation of S190814bv, and given the characteristics of the signal, the LIGO and Virgo Collaborations delivered a relatively narrow localisation in low latency - a 50% (90%) credible area of 5 deg^2^ (23 deg^2^) - despite the relatively large distance of 267 52 Mpc. ElectromagNetic counterparts of GRAvitational wave sources at the VEry Large Telescope (ENGRAVE) collaboration members carried out an intensive multi-epoch, multi-instrument observational campaign to identify the possible optical and near infrared counterpart of the event. In addition, the ATLAS, GOTO, GRAWITA-VST, Pan-STARRS, and VINROUGE projects also carried out a search on this event. In this paper, we describe the combined observational campaign of these groups. Our observations allow us to place limits on the presence of any counterpart and discuss the implications for the kilonova (KN), which was possibly generated by this NS-BH merger, and for the strategy of future searches. The typical depth of our wide-field observations, which cover most of the projected sky localisation probability (up to 99.8%, depending on the night and filter considered), is r 22 (resp. K 21) in the optical (resp. near infrared). We reach deeper limits in a subset of our galaxy-targeted observations, which cover a total 50% of the galaxy-mass-weighted localisation probability. Altogether, our observations allow us to exclude a KN with large ejecta mass M>~0:1M_{sun}_ to a high (>90%) confidence, and we can exclude much smaller masses in a sub-sample of our observations. This disfavours the tidal disruption of the neutron star during the merger. Despite the sensitive instruments involved in the campaign, given the distance of S190814bv, we could not reach sufficiently deep limits to constrain a KN comparable in luminosity to AT 2017gfo on a large fraction of the localisation probability. This suggests that future (likely common) events at a few hundred megaparsecs will be detected only by large facilities with both a high sensitivity and large field of view. Galaxytargeted observations can reach the needed depth over a relevant portion of the localisation probability with a smaller investment of resources, but the number of galaxies to be targeted in order to get a fairly complete coverage is large, even in the case of a localisation as good as that of this event.
- ID:
- ivo://CDS.VizieR/J/A+A/479/141
- Title:
- Iz photometry, RV and EW(Li) in IC 4665
- Short Name:
- J/A+A/479/141
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The so-called lithium depletion boundary (LDB) provides a secure and independent tool for deriving the ages of young open clusters. In this context, our goal is to determine membership for a sample of 147 photometrically selected candidates of the young open cluster IC 4665 and to use confirmed members to establish an age based on the LDB. Employing the FLAMES multi-object spectrograph on VLT/UT2, we have obtained intermediate-resolution spectra of the cluster candidates. The spectra were used to measure radial velocities and to infer the presence of the LiI 670.8nm doublet and H{alpha} emission.
- ID:
- ivo://CDS.VizieR/B/jcmt
- Title:
- Jame Clerk Maxwell Telescope Science Archive
- Short Name:
- B/jcmt
- Date:
- 20 Feb 2022 06:15:12
- Publisher:
- CDS
- Description:
- The JCMT Science Archive (JSA), a collaboration between the CADC and EOA, is the official distribution site for observational data obtained with the James Clerk Maxwell Telescope (JCMT) on Mauna Kea, Hawaii. The JSA search interface is provided by the CADC Search tool, which provides generic access to the complete set of telescopic data archived at the CADC. Help on the use of this tool is provided via tooltips. For additional information on instrument capabilities and data reduction, please consult the SCUBA-2 and ACSIS instrument pages provided on the JAC maintained JCMT pages. JCMT-specific help related to the use of the CADC AdvancedSearch tool is available from the JAC.
- ID:
- ivo://CDS.VizieR/J/A+A/648/A38
- Title:
- J1717-3342 and J1744-3116 CO spectra
- Short Name:
- J/A+A/648/A38
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The chemistry of the diffuse interstellar medium is driven by the combined influences of cosmic rays, ultraviolet (UV) radiation, and turbulence. Previously detected at the outer edges of photodissociation regions (PDRs) and formed from the reaction of C^+^ and OH, CO^+^ is the main chemical precursor of HCO^+^ and CO in a thermal, cosmic-ray, and UV-driven chemistry. Our aim was to test whether the thermal cosmic-ray and UV-driven chemistry is producing CO in diffuse interstellar molecular gas through the intermediate formation of CO^+^ We searched for CO^+^ absorption with the Atacama Large Millimeter Array (ALMA) toward two quasars with known Galactic foreground absorption from diffuse interstellar gas, J1717-3342 and J1744-3116, targeting the two strongest hyperfine components of the J=2-1 transition near 236GHz. We could not detect CO^+^ but obtained sensitive upper limits toward both targets. The derived upper limits on the CO^+^ column densities represent about 4% of the HCO^+^ column densities. The corresponding upper limit on the CO^+^ abundance relative to H_2_ is <1.2x10^-10^. The non-detection of CO^+^ confirms that HCO^+^ is mainly produced in the reaction between oxygen and carbon hydrides, CH2^+^ or CH3^+^, induced by suprathermal processes, while CO^+^ and HOC^+^ result from reactions of C^+^ with OH and H_2_O. The densities r equired to form CO molecules at low extinction are consistent with this scheme.
- ID:
- ivo://CDS.VizieR/J/AJ/129/1311
- Title:
- J-band photometry of ADBS Galaxies
- Short Name:
- J/AJ/129/1311
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the results of a J-band study of the H I-selected Arecibo Dual-Beam Survey (ADBS, Cat. J/ApJS/130/177) and Arecibo Slice Survey (AS, Cat. J/ApJS/119/159) galaxy samples using Two Micron All Sky Survey data.
- ID:
- ivo://CDS.VizieR/J/A+A/555/A2
- Title:
- J-band variability of AGN
- Short Name:
- J/A+A/555/A2
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Spectral energy distribution and its variability are basic tools for understanding the physical processes operating in active galactic nuclei (AGN). In this paper we report the results of a one-year near infra red (NIR) and optical monitoring of a sample of 22 AGN known to be {gamma}-ray emitters, aimed at discovering correlations between optical and {gamma}-ray emission. We observed our objects with the Rapid Eye Mount (REM) telescope in J, H, K, and R bands nearly twice every month during their visibility window and derived light curves and spectral indexes. We also analyzed the {gamma}-ray data from the Fermi {gamma}-ray Space Telescope, making weekly averages.
- ID:
- ivo://CDS.VizieR/J/ApJ/817/167
- Title:
- JCMT Gould Belt Survey: dense cores in Orion B
- Short Name:
- J/ApJ/817/167
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a first look at the SCUBA-2 observations of three sub-regions of the Orion B molecular cloud: LDN 1622, NGC 2023/2024, and NGC 2068/2071, from the JCMT Gould Belt Legacy Survey. We identify 29, 564, and 322 dense cores in L1622, NGC 2023/2024, and NGC 2068/2071 respectively, using the SCUBA-2 850{mu}m map, and present their basic properties, including their peak fluxes, total fluxes, and sizes, and an estimate of the corresponding 450{mu}m peak fluxes and total fluxes, using the FellWalker source extraction algorithm. Assuming a constant temperature of 20K, the starless dense cores have a mass function similar to that found in previous dense core analyses, with a Salpeter-like slope at the high-mass end. The majority of cores appear stable to gravitational collapse when considering only thermal pressure; indeed, most of the cores which have masses above the thermal Jeans mass are already associated with at least one protostar. At higher cloud column densities, above 1-2x10^23^/cm2, most of the mass is found within dense cores, while at lower cloud column densities, below 1x10^23^/cm2, this fraction drops to 10% or lower. Overall, the fraction of dense cores associated with a protostar is quite small (<8%), but becomes larger for the densest and most centrally concentrated cores. NGC 2023/2024 and NGC 2068/2071 appear to be on the path to forming a significant number of stars in the future, while L1622 has little additional mass in dense cores to form many new stars.