- ID:
- ivo://CDS.VizieR/J/A+A/342/313
- Title:
- ISO HDF observations from PRETI method
- Short Name:
- J/A+A/342/313
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We have developed a new ISOCAM data reduction technique based on wavelet analysis, especially designed for the detection of faint sources in mid-infrared surveys. This method, the Pattern REcognition Technique for Isocam data (PRETI) has been used to reduce the observations of the Hubble Deep Field (HDF) and flanking fields with ISOCAM at 6.75 (LW2) and 15{mu}m (LW3) (Rowan-Robinson et al. 1997MNRAS.289..490R). Simulations of ISOCAM data allow us to test the photometric accuracy and completeness of the reduction. According to these simulations, the PRETI source list is 95% complete in the 15{mu}m band at 200{mu}Jy and in the 6.75{mu}m band at 65{mu}Jy, using detection thresholds which minimize the number of false detections. We detect 49 objects in the ISO-HDF at high confidence secure level, 42 in the LW3 filter, 3 in the LW2 filter, and 4 in both filters. An additional, less secure, list of 100 sources is presented, of which 89 are detected at 15{mu}m only, 7 at 6.75{mu}m only and 4 in both filters. All ISO-HDF objects detected in the HDF itself have optical or infrared counterparts, except for one from the additional list. All except one of the radio sources detected in the field by Fomalont et al. (1997ApJ...475L...5F) are detected with ISOCAM. Using a precise correction for the field of view distortion of ISOCAM allows us to separate blended sources. This, together with the fact that PRETI allows to correct data on the tail of cosmic rays glitches, lead us to produce deeper source lists than previous authors. Our list of bright sources agree with those of Desert et al. (1999A&A...342..363D) in both filters, and with those of Goldschmidt et al. (1997MNRAS.289..465G) in the LW3 filter, with systematic difference in photometry. ISO is an ESA project with instruments funded by ESA Member States (especially the PI countries: France, Germany, The Netherlands and the United Kingdom) and with participation of ISAS and NASA.
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Search Results
- ID:
- ivo://CDS.VizieR/J/A+A/359/865
- Title:
- ISOPHOT 170{mu}m Serendipity Survey I.
- Short Name:
- J/A+A/359/865
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Serendipity slew survey measurements were acquired with the ISOPHOT C200 detector installed on the ISO mission. The C200 detector is a 2x2 pixel array of stressed Ge:Ga with a pixel size of 89.4arcsec, and was used in conjunction with the C160 broad-band filter (reference wavelength 170{mu}m, width 89{mu}m). During the lifetime of the ISO mission, about 550 hours of measurements have been gathered with more than 12000 slews. From the slew data with low (100{mu}m<=15MJy/sr) cirrus background, 115 well-observed sources with a high signal to noise ratio in all detector pixels having a galaxy association were extracted. The 170{mu}m fluxes measured from the Serendipity slews have been put on an absolute flux level by using calibration sources observed additionally with the photometric mapping mode of ISOPHOT. For all but a few galaxies, the 170{mu}m fluxes are determined for the first time, which represents a significant increase in he number of galaxies with measured Far-Infrared (FIR) fluxes beyond the IRAS 100{mu}m limit.
- ID:
- ivo://CDS.VizieR/J/A+A/422/39
- Title:
- ISOPHOT 170{mu}m Serendipity Survey II.
- Short Name:
- J/A+A/422/39
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The ISOPHOT Serendipity Sky Survey strip-scanning measurements covering ~15% of the far-infrared (FIR) sky at 170{mu}m were searched for compact sources associated with optically identified galaxies. Compact Serendipity Survey sources with a high signal-to-noise ratio in at least two ISOPHOT C200 detector pixels were selected that have a positional association with a galaxy identification in the NED and/or Simbad databases and a galaxy counterpart visible on the Digitized Sky Survey plates. A catalog with 170{mu}m fluxes for more than 1900 galaxies has been established, 200 of which were measured several times.
- ID:
- ivo://CDS.VizieR/J/A+A/466/1205
- Title:
- ISOPHOT 170{mu}m Serendipity Survey. IV
- Short Name:
- J/A+A/466/1205
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The 170 micron far-infrared slew data of the ISOPHOT Serendipity Survey (ISOSS) has been assembled to a sky atlas with ~15% sky coverage. The redundant information of the brightnesss at slew crossings has been used to globally rescale and homogenize the slew brightnesses, leading to significantly increased photometric accuracy and reproducibility as well as the homogeneity of the maps. The corrected slew data were remapped with a constant grid size of 22.4arcsec onto 124 maps in galactic coordinates.
- 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/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.
- ID:
- ivo://CDS.VizieR/J/MNRAS/469/2163
- Title:
- JCMT Plane Survey. first complete data release
- Short Name:
- J/MNRAS/469/2163
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the first data release of the James Clerk Maxwell Telescope Plane Survey (JPS), the JPS Public Release 1. JPS is an 850-{mu}m continuum survey of six fields in the northern inner Galactic plane in a longitude range of l=7{deg}-63{deg}, made with the Submillimetre Common-User Bolometer Array 2. This first data release consists of emission maps of the six JPS regions with an average pixel-to-pixel noise of 7.19mJy/beam, when smoothed over the beam, and a compact source catalogue containing 7813 sources. The 95 per cent completeness limits of the catalogue are estimated at 0.04Jy/beam and 0.3Jy for the peak and integrated flux densities, respectively. The emission contained in the compact source catalogue is 42+/-5 per cent of the total and, apart from the large-scale (greater than 8 arcmin) emission, there is excellent correspondence with features in the 500-{mu}m Herschel maps. We find that, with two-dimensional matching, 98 {\pm} 2 per cent of sources within the fields centred at l=20{deg}, 30{deg}, 40{deg} and 50{deg} are associated with molecular clouds, with 91+/-3 per cent of the l=30{deg} and 40{deg} sources associated with dense molecular clumps. Matching the JPS catalogue to Herschel 70-{mu}m sources, we find that 38+/-1 per cent of sources show evidence of ongoing star formation. The JPS Public Release 1 images and catalogue will be a valuable resource for studies of star formation in the Galaxy and the role of environment and spiral arms in the star formation process.
- ID:
- ivo://CDS.VizieR/J/MNRAS/453/4264
- Title:
- JCMT Plane Survey: l=30{deg} field
- Short Name:
- J/MNRAS/453/4264
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present early results from the JCMT (James Clerk Maxwell Telescope) Plane Survey (JPS), which has surveyed the northern inner Galactic plane between longitudes l=7{deg} and l=63{deg} in the 850-{mu}m continuum with SCUBA-2 (Submm Common-User Bolometer Array 2), as part of the JCMT Legacy Survey programme. Data from the l=30{deg} survey region, which contains the massive-star-forming regions W43 and G29.96, are analysed after approximately 40 percent of the observations had been completed. The pixel-to-pixel noise is found to be 19mJy/beam after a smooth over the beam area, and the projected equivalent noise levels in the final survey are expected to be around 10mJy/beam. An initial extraction of compact sources was performed using the FellWalker method, resulting in the detection of 1029 sources above a 5{sigma} surface-brightness threshold. The completeness limits in these data are estimated to be around 0.2Jy/beam (peak flux density) and 0.8 Jy (integrated flux density) and are therefore probably already dominated by source confusion in this relatively crowded section of the survey. The flux densities of extracted compact sources are consistent with those of matching detections in the shallower APEX (Atacama Pathfinder Experiment) Telescope Large Area Survey of the Galaxy (ATLASGAL) survey. We analyse the virial and evolutionary state of the detected clumps in the W43 star-forming complex and find that they appear younger than the Galactic-plane average.
- ID:
- ivo://CDS.VizieR/J/AJ/160/115
- Title:
- JHK observation of 75 OB stars in Cyg OB2
- Short Name:
- J/AJ/160/115
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present results of a high angular resolution survey of massive OB stars in the Cygnus OB2 association that we conducted with the Near-Infrared Imager camera and ALTAIR adaptive optics system of the Gemini North telescope. We observed 74 O- and early-B-type stars in Cyg OB2 in the JHK infrared bands in order to detect binary and multiple companions. The observations are sensitive to equal-brightness pairs at separations as small as 0.08", and progressively fainter companions are detectable out to {Delta}K=9mag at a separation of 2". This faint contrast limit due to read noise continues out to 10" near the edge of the detector. We assigned a simple probability of chance alignment to each companion based upon its separation and magnitude difference from the central target star and upon areal star counts for the general star field of Cyg OB2. Companion stars with a field membership probability of less than 1% are assumed to be physical companions. This assessment indicates that 47% of the targets have at least one resolved companion that is probably gravitationally bound. Including known spectroscopic binaries, our sample includes 27 binary, 12 triple, and 9 systems with 4 or more components. These results confirm studies of high-mass stars in other environments that find that massive stars are born with a high-multiplicity fraction. The results are important for the placement of the stars in the Hertzsprung-Russell diagram, the interpretation of their spectroscopic analyses, and for future mass determinations through measurement of orbital motion.
- ID:
- ivo://CDS.VizieR/J/MNRAS/361/211
- Title:
- JHK photometry of brown dwarfs in Orion
- Short Name:
- J/MNRAS/361/211
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We report the results of a deep near-infrared (JHK) survey of the outer parts of the Trapezium Cluster with Gemini South/Flamingos. 396 sources were detected in a 26-arcmin^2^ area, including 138 brown dwarf candidates, defined as M<0.075M_{sun}_ for an assumed age of 1Myr. Only 33 of the brown dwarf candidates are planetary mass candidates with estimated masses in the range 0.003<M<0.012M_{sun}_. In an extinction-limited sample (AV<5) complete to approximately 0.005M_{sun}_ (5M_Jup_) the mass function appears to drop by a factor of 2 at the deuterium burning threshold, i.e. at planetary masses. After allowing for background contamination it is likely that planetary mass objects at 3-13M_Jup_ number <10% of the cluster population, with an upper limit of 13%. Analysis of the spatial distribution of stars and brown dwarf candidates suggests that brown dwarfs and very low-mass stars (M<0.1M_{sun}_) are less likely than more massive stars to have wide (>150AU) binary companions.
