- ID:
- ivo://CDS.VizieR/J/MNRAS/461/1734
- Title:
- HAWK-I JHK photometry of the Orion Nebula Cloud
- Short Name:
- J/MNRAS/461/1734
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Due to its youth, proximity and richness, the Orion nebula cloud (ONC) is an ideal testbed to obtain a comprehensive view on the initial mass function (IMF) down to the planetary mass regime. Using the HAWK-I camera at the VLT, we have obtained an unprecedented deep and wide near-infrared JHK mosaic of the ONC (90 per cent completeness at K ~19.0mag, 22x28 arcmin^2^). Applying the most recent isochrones and accounting for the contamination of background stars and galaxies, we find that ONC's IMF is bimodal with distinct peaks at about 0.25 and 0.025M_{sun}_ separated by a pronounced dip at the hydrogen burning limit (0.08M_{sun}_), with a depth of about a factor of 2-3 below the log-normal distribution. Apart from ~920 low-mass stars (M<1.4M_{sun}_) the IMF contains ~760 brown dwarf candidates and ~160 isolated planetary mass object candidates with M>0.005M_{sun}_, hence about 10 times more substellar candidates than known before. The substellar IMF peak at 0.025M_{sun}_ could be caused by brown dwarfs and isolated planetary mass objects which have been ejected from multiple systems during the early star formation process or from circumstellar discs.
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Search Results
- ID:
- ivo://CDS.VizieR/J/A+A/470/957
- Title:
- H-band images of IRAS 19312+1950
- Short Name:
- J/A+A/470/957
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We obtained H-band polarimetric data of IRAS 19312+1950 using the near-infrared camera (CIAO) on the 8m Subaru telescope. In order to investigate the physical properties of the central star and the nebula, we performed dust radiative transfer modeling and compared the model results with the observed spectral energy distributions (SEDs), the radial profiles of the total intensity image, and the fraction of linear polarization map. The total intensity image shows a nearly spherical core with ~3" radius, an S-shaped arm extending ~10" in the northwest to southeast direction, and an extended lobe towards the southwest. The polarization map shows a centro-symmetric vector alignment in almost the entire nebula and low polarizations along the S-shaped arm. These results suggest that the nebula is accompanied by a central star, and the S-shaped arm has a physically ring-like structure. From our radiative transfer modeling, we estimated the stellar temperature, the bolometric luminosity, and the current mass-loss rate to be 2800K, 7000L_{sun}_, and 5.3x10^-6^M_{sun}_/yr, respectively. Taking into account previous observational results, such as the detection of SiO maser emissions and silicate absorption feature in the 10{mu}m spectrum, our dust radiative transfer analysis based on our NIR imaging polarimetry suggests that (1) the central star of IRAS 19312+1950 is likely to be an oxygen-rich, dust-enshrouded AGB star and (2) most of the circumstellar material originates from other sources (e.g. ambient dark clouds) rather than as a result of mass loss from the central star.
- ID:
- ivo://CDS.VizieR/J/A+A/403/493
- Title:
- H-band observation of Chandra Deep Field South
- Short Name:
- J/A+A/403/493
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We report preliminary results of our H-band survey of the Chandra Deep Field South (CDFS). The observations were made using SofI on the NTT, and cover 0.027 square degrees with a 50% completeness limit of H=20.5, and 0.17 square degrees with a 50% completeness limit of H=19.8. We used SExtractor to extract sources from our fields. In total we have detected 4819 objects. Star-galaxy separation was performed using the SExtractor parameter "stellarity index". All objects with an index of 0.5 or lower were classified as galaxies. According to this criterion, 80% of our detections are galaxies. We then compare our results with previous observations of the CDFS. Our astrometric solutions are in good agreement with the Las Campanas Infrared Survey (LCIRS), the COMBO-17 and the ESO-EIS surveys. The photometry of our catalog compares satisfactorily with the results of the LCIRS, as well as with the GOODS data. Galaxy number counts are presented and compared with the LCIRS results. The present data are intended to complement the recent and future multi-wavelength observations of the CDFS and will be used, in conjunction with additional multiband photometry, to find counterparts of the upcoming mid-infrared surveys with SIRTF.
- ID:
- ivo://CDS.VizieR/J/ApJ/796/64
- Title:
- H{beta} and Ly{alpha} emitting galaxies at z~2
- Short Name:
- J/ApJ/796/64
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We compare the H{beta} line strengths of 1.90<z<2.35 star-forming galaxies observed with the near-IR grism of the Hubble Space Telescope with ground-based measurements of Ly{alpha} from the HETDEX Pilot Survey and narrow-band imaging. By examining the line ratios of 73 galaxies, we show that most star-forming systems at this epoch have a Ly{alpha} escape fraction below ~6%.
- ID:
- ivo://CDS.VizieR/J/ApJ/821/113
- Title:
- HCG and RSCG compact group galaxies with WISE
- Short Name:
- J/ApJ/821/113
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Compact groups provide an environment to study the growth of galaxies amid multiple prolonged interactions. With their dense galaxy concentrations and relatively low velocity dispersions, compact groups mimic the conditions of hierarchical galaxy assembly. Compact group galaxies are known to show a bimodality in Spitzer IRAC infrared color space: galaxies are preferentially either quiescent with low specific star formation rates (SSFRs) or prolifically forming stars-galaxies with moderate levels of specific star formation are rare. Previous Spitzer IRAC studies identifying this "canyon" have been limited by small number statistics. We utilize whole-sky Wide-field Infrared Survey Explorer (WISE) data to study 163 compact groups, thereby tripling our previous sample and including more galaxies with intermediate mid-IR colors indicative of moderate SSFRs. We define a distinct WISE mid-IR color space (log[f_12_/f_4.6_]) versus (log[f_22_/f_3.4_]) that we use to identify canyon galaxies from the larger sample. We confirm that compact group galaxies show a bimodal distribution in the mid-infrared and identify 37 canyon galaxies with reliable photometry and intermediate mid-IR colors. Morphologically, we find that the canyon harbors a large population of both Sa-Sbc and E/S0 type galaxies, and that they fall on the optical red sequence rather than the green valley. Finally, we provide a catalog of WISE photometry for 567 of 652 galaxies selected from the sample of 163 compact groups.
- ID:
- ivo://CDS.VizieR/J/ApJ/791/55
- Title:
- HD 189733b in transit light curve
- Short Name:
- J/ApJ/791/55
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We report near-infrared spectroscopy of the gas giant planet HD 189733b in transit. We used the Hubble Space Telescope Wide Field Camera 3 (HST WFC3) with its G141 grism covering 1.1 {mu}m to 1.7 {mu}m and spatially scanned the image across the detector at 2''/s. When smoothed to 75 nm bins, the local maxima of the transit depths in the 1.15 {mu}m and 1.4 {mu}m water vapor features are, respectively, 83+/-53 ppm and 200+/-47 ppm greater than the local minimum at 1.3 {mu}m. We compare the WFC3 spectrum with the composite transit spectrum of HD 189733b assembled by Pont et al., extending from 0.3 {mu}m to 24 {mu}m. Although the water vapor features in the WFC3 spectrum are compatible with the model of non-absorbing, Rayleigh-scattering dust in the planetary atmosphere, we also re-interpret the available data with a clear planetary atmosphere. In the latter interpretation, the slope of increasing transit depth with shorter wavelengths from the near infrared, through the visible, and into the ultraviolet is caused by unocculted star spots, with a smaller contribution of Rayleigh scattering by molecular hydrogen in the planet's atmosphere. At relevant pressures along the terminator, our model planetary atmosphere's temperature is ~700 K, which is below the condensation temperatures of sodium- and potassium-bearing molecules, causing the broad wings of the spectral lines of Na I and K I at 0.589 {mu}m and 0.769 {mu}m to be weak.
- ID:
- ivo://CDS.VizieR/J/ApJ/655/51
- Title:
- HDFS IRAC observations of 2<z<3.5 galaxies
- Short Name:
- J/ApJ/655/51
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We analyze very deep HST, VLT, and Spitzer photometry of galaxies at 2<z<3.5 in the Hubble Deep Field-South. The sample is selected from the deepest public K-band imaging currently available. We show that the rest-frame U-V versus V-J color-color diagram is a powerful diagnostic of the stellar populations of distant galaxies. Galaxies with red rest-frame U-V colors are generally red in rest-frame V-J as well. However, at a given U-V color a range in V-J colors exists, and we show that this allows us to distinguish young, dusty galaxies from old, passively evolving galaxies. We quantify the effects of IRAC photometry on estimates of masses, ages, and the dust content of z>2 galaxies.
- ID:
- ivo://CDS.VizieR/J/MNRAS/462/1989
- Title:
- HerMES Large Mode Survey catalogue
- Short Name:
- J/MNRAS/462/1989
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Selecting sources with rising flux densities towards longer wavelengths from Herschel/Spectral and Photometric Imaging Receiver (SPIRE) maps is an efficient way to produce a catalogue rich in high-redshift (z>4) dusty star-forming galaxies. The effectiveness of this approach has already been confirmed by spectroscopic follow-up observations, but the previously available catalogues made this way are limited by small survey areas. Here we apply a map-based search method to 274deg^2^ of the Herschel Multi-tiered Extragalactic Survey (HerMES) Large Mode Survey and create a catalogue of 477 objects with SPIRE flux densities S_500_>S_350_>S_250_ and a 5{sigma} cut-off S_500_>52mJy. From this catalogue we determine that the total number of these 'red' sources is at least an order of magnitude higher than predicted by galaxy evolution models. These results are in agreement with previous findings in smaller HerMES fields; however, due to our significantly larger sample size we are also able to investigate the shape of the red source counts for the first time. We have obtained spectroscopic redshift measurements for two of our sources using the Atacama Large Millimeter/submillimeter Array. The redshifts z=5.1 and 3.8 confirm that with our selection method we can indeed find high-redshift dusty star-forming galaxies.
- ID:
- ivo://CDS.VizieR/J/MNRAS/473/1751
- Title:
- Herschel Bright Sources (HerBS)
- Short Name:
- J/MNRAS/473/1751
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the Herschel Bright Sources (HerBS) sample, a sample of bright, high-redshift Herschel sources detected in the 616.4deg^2^ Herschel Astrophysical Terahertz Large Area Survey. The HerBS sample contains 209 galaxies, selected with a 500um flux density greater than 80mJy and an estimated redshift greater than 2. The sample consists of a combination of hyperluminous infrared galaxies and lensed ultraluminous infrared galaxies during the epoch of peak cosmic star formation. In this paper, we present Submillimetre Common-User Bolometer Array 2 (SCUBA-2) observations at 850um of 189 galaxies of the HerBS sample, 152 of these sources were detected. We fit a spectral template to the Herschel-Spectral and Photometric Imaging Receiver (SPIRE) and 850um SCUBA-2 flux densities of 22 sources with spectroscopically determined redshifts, using a two-component modified blackbody spectrum as a template. We find a cold- and hot-dust temperature of 21.29^+1.35^_-1.66_ and 45.80^+2.88^_-3.48_K, a cold-to-hot dust mass ratio of 26.62^+5.61^_-6.74_ and a {beta} of 1.83^+0.14^_-0.28_. Thee poor quality of the fit suggests that the sample of galaxies is too diverse to be explained by our simple model. Comparison of our sample to a galaxy evolution model indicates that the fraction of lenses are high. Out of the 152 SCUBA-2 detected galaxies, the model predicts 128.4+/-2.1 of those galaxies to be lensed (84.5 per cent). The SPIRE 500um flux suggests that out of all 209 HerBS sources, we expect 158.1+/-1.7 lensed sources, giving a total lensing fraction of 76 per cent.
- ID:
- ivo://CDS.VizieR/J/A+A/590/A72
- Title:
- Herschel counterparts of SDC
- Short Name:
- J/A+A/590/A72
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The goal of this paper is to identify which of the clouds from the Spitzer Dark Cloud catalogue (Peretto & Fuller, 2009, Cat. J/A+A/505/405) are real, which are artefacts. For this we used Herschel Hi-GAL (Molinari et al., 2010PASP..122..314M) column density maps and search for spatial associations between Spitzer Dark Cloud and Herschel column density peaks. Description: This table provides some of the key properties of the Spitzer Dark Clouds that we estimated using the Herschel data and used to disentangle between real and spurious clouds. For each cloud of the Peretto & Fuller (2009, Cat. J/A+A/505/405) catalogue we give the cloud name, the cloud equivalent radius, the average Herschel column density within the boundaries of the SDCs, the average Herschel column density immediately outside the boundary of the SDCs, the Herschel column density noise at the position of the SDC, the Herschel column density peak within the boundaries of the SDCs, the value for criterion c1, the value for criterion c2, the value for criterion c3, and a tag that indicates if the cloud has been identified as real by our automated detection scheme based on the values of c1 and c2. This tag can take a number of values. These are: 'y' for yes; n for no; 'sat' for a SDC entirely located in a saturated portion of the Herschel images; 'ysat' for a cloud that is considered real despite being partially saturated; 'out' for a SDC that is not covered by Herschel images; 'yout' for a cloud that is considered real despite being partially covered by Herschel images; 'nout' for a cloud considered spurious despite being partially covered by Herschel images. Also, note that the column referring to the equivalent radius Req is the same quantity as the one quoted in Table 1 column 11 of Peretto & Fuller (2009, Cat. J/A+A/505/405). However, these latter values should be discarded since a mistake has been found in the calculation of the equivalent radius. Only the new values, the ones provided in Table 1 column 2 of this paper should be considered.
