- ID:
- ivo://CDS.VizieR/J/A+A/649/A84
- Title:
- IR band features around HD100546
- Short Name:
- J/A+A/649/A84
- Date:
- 22 Feb 2022
- Publisher:
- CDS
- Description:
- Carbonaceous nanograins are present at the surface of protoplanetary disks around Herbig Ae/Be stars, where most of the ultraviolet energy from the central star is dissipated. Efficiently coupled to the gas, they are unavoidable to understand the physics and chemistry of these disks. Furthermore, nanograins are able to trace the outer flaring parts of the disk and possibly the gaps from which the larger grains are missing. However, their evolution through the disks, from internal to external regions, is only poorly understood so far. Our aim is to examine the spatial distribution and evolution of the nanodust emission in the emblematic (pre-)transitional protoplanetary disk HD 100546. This disk shows many structures (annular gaps, rings, and spirals) and reveals very rich carbon nanodust spectroscopic signatures (aromatic, aliphatic) in a wide spatial range of the disk (~20-200au). We analysed adaptive optics spectroscopic observations in the 3-4um range (angular resolution of ~0.1") and imaging and spectroscopic observations in the 8-12um range (angular resolution of ~0.3"). The hyperspectral cube was decomposed into a sum of spatially coherent dust components using a Gaussian decomposition algorithm. We compared the data to model predictions using the heterogeneous dust evolution model for interstellar solids (THEMIS), which is integrated in the radiative transfer code POLARIS by calculating the thermal and stochastic heating of micro- and nanometre-sized dust grains for a given disk structure. We find that the aromatic features at 3.3, 8.6, and 11.3um, and the aliphatic features between 3.4 and 3.5um are spatially extended; each band shows a specific morphology dependent on the local physical conditions. The aliphatic-to-aromatic band ratio, 3.4/3.3, increases with the distance from the star from ~0.2 (at 0.2" or 20au) to ~0.45 (at 1" or 100au), suggesting UV processing. In the 8-12um observed spectra, several features characteristic of aromatic particles and crystalline silicates are detected. Their relative contribution changes with the distance to the star. The model predicts that the features and adjacent continuum are due to different combinations of grain sub-populations, in most cases with a high dependence on the intensity of the UV field. The model reproduces the spatial emission profiles of the bands well, except for the inner 20-40au, where the observed emission of the 3.3 and 3.4um bands is, unlike the predictions, flat and no longer increases with the UV field. With our approach that combines observational data in the near- to mid-IR and disk modelling, we deliver constraints on the spatial distribution of nano-dust particles as a function of the disk structure and radiation field.
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Search Results
- ID:
- ivo://CDS.VizieR/J/ApJ/876/132
- Title:
- IR-bright DOGs viewed with Subaru HSC
- Short Name:
- J/ApJ/876/132
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We report on the optical properties of infrared (IR)-bright dust-obscured galaxies (DOGs) that are defined as (i-[22])_AB_>=7.0. Because supermassive black holes (SMBHs) in IR-bright DOGs are expected to be rapidly growing in the major-merger scenario, they provide useful clues for understanding the coevolution of SMBHs and their host galaxies. However, the optical properties of IR-bright DOGs remain unclear because the optical emission of a DOG is very faint. By combining ~105deg^2^ images of the optical, near-IR, and mid-IR data obtained from the Subaru Hyper Suprime-Cam (HSC) survey, the VISTA VIKING survey, and the Wide-field Infrared Survey Explorer all-sky survey, respectively, 571 IR-bright DOGs were selected. We found that IR-bright DOGs show a redder (g-z)_AB_ color than do other populations of dusty galaxies, such as ultraluminous IR galaxies (ULIRGs) at a similar redshift, with a significantly large dispersion. Among the selected DOGs, star formation (SF)-dominated DOGs show a relatively red color, while active galactic nucleus (AGN)-dominated DOGs show a rather blue color in optical. This result is consistent with the idea that the relative AGN contribution in the optical emission becomes more significant at a later stage in the major-merger scenario. We discovered eight IR-bright DOGs showing a significant blue excess in blue HSC bands. This blue excess can be interpreted as a leaked AGN emission that is either a directly leaking or a scattered AGN emission, as proposed for some blue-excess Hot DOGs in earlier studies.
- ID:
- ivo://CDS.VizieR/J/MNRAS/478/2
- Title:
- IR-bright gamma-ray burst host galaxies
- Short Name:
- J/MNRAS/478/2
- Date:
- 17 Jan 2022 00:28:54
- Publisher:
- CDS
- Description:
- We identify and explore the properties of an infrared-bright gamma-ray burst (GRB) host population. Candidate hosts are selected by coincidence with sources in WISE, with matching to random coordinates and a false alarm probability analysis showing that the contamination fraction is ~0.5. This methodology has already identified the host galaxy of GRB 080517. We combine survey photometry from Pan-STARRS, SDSS, APASS, 2MASS, GALEX, and WISE with our own WHT/ACAM and VLT/X-shooter observations to classify the candidates and identify interlopers. Galaxy SED fitting is performed using MAGPHYS, in addition to stellar template fitting, yielding 13 possible IR-bright hosts. A further seven candidates are identified from the previously published work. We report a candidate host for GRB 061002, previously unidentified as such. The remainder of the galaxies have already been noted as potential hosts. Comparing the IR-bright population properties including redshift z, stellar mass M*, star formation rate SFR, and V-band attenuation A_V_ to GRB host catalogues in the literature, we find that the infrared-bright population is biased towards low z, high M*, and high A_V_. This naturally arises from their initial selection - local and dusty galaxies are more likely to have the required IR flux to be detected in WISE. We conclude that while IR-bright GRB hosts are not a physically distinct class, they are useful for constraining existing GRB host populations, particularly for long GRBs.
- ID:
- ivo://CDS.VizieR/J/MNRAS/394/1875
- Title:
- IR colours of MASH planetary nebulae
- Short Name:
- J/MNRAS/394/1875
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We have analysed the near-infrared (NIR) and far-infrared (FIR) colours of MASH I and MASH II (the Macquarie/AAO/Strasbourg surveys, Cat. <V/127>) planetary nebulae (PNe), using data deriving from the Two-Micron All-Sky Survey and Infrared Astronomical Satellite. We were able to identify ~5 per cent of the sources in the NIR, and a slightly larger fraction (~12 per cent) in the FIR. It is concluded that whilst the NIR colours of these nebulae are consistent with those of less evolved (and higher surface brightness) PNe, their FIR colours are markedly different. This disparity is likely to arise as a result of an evolution in dust temperatures, in their line emission characteristics, and in the relative contributions of the 8.6 and 11.3um polycyclic aromatic hydrocarbon emission features. A rump of~9 per cent of the detected sources have values log[F(25um)/F(60um)] which are lower than can be explained in terms of normal nebular evolution, however. If these are comparable in nature to the undetected PNe, then this would argue that ~1 in 10 of MASH I and II nebulae may represent galactic H ii regions, Stromgren spheres, symbiotic nebulae or other unrelated categories of source.
- ID:
- ivo://CDS.VizieR/J/ApJ/563/L49
- Title:
- IR counterpart of the X-ray pulsar 1E 2259+586
- Short Name:
- J/ApJ/563/L49
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present near-infrared and optical observations of the field of the anomalous X-ray pulsar 1E 2259+586 taken with the Keck telescope. We derive a sub-arcsecond Chandra position and tie it to our optical reference frame using other stars in the field. We find a very faint source, K_S_=21.7+/-0.2mag, with a position coincident with the Chandra position. We argue that this is the counterpart. In the J, I, and R bands, we derive (2{sigma}) limits of 23.8, 25.6, and 26.4mag, respectively. As with 4U 0142+61, for which a counterpart has previously been found, our results are inconsistent with models in which the source is powered by accretion from a disk but may be consistent with the magnetar model.
- ID:
- ivo://CDS.VizieR/J/ApJ/756/28
- Title:
- IR counterparts to submm H-ATLAS galaxies
- Short Name:
- J/ApJ/756/28
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We use Spitzer-IRAC data to identify near-infrared counterparts to submillimeter galaxies detected with Herschel-SPIRE at 250{mu}m in the Herschel Astrophysical Terahertz Large Area Survey. Using a likelihood ratio analysis we identify 146 reliable IRAC counterparts to 123 SPIRE sources out of the 159 in the survey area. We find that, compared to the field population, the SPIRE counterparts occupy a distinct region of the 3.6 and 4.5{mu}m color-magnitude space, and we use this property to identify 23 further counterparts to 13 SPIRE sources. The IRAC identification rate of 86% is significantly higher than those that have been demonstrated with wide-field ground-based optical and near-IR imaging of Herschel fields. We estimate a false identification rate of 3.6%, corresponding to 4-5 sources. Among the 73 counterparts that are undetected in Sloan Digital Sky Survey, 57 have both 3.6 and 4.5{mu}m coverage. Of these, 43 have [3.6]-[4.5]>0, indicating that they are likely to be at z>~1.4. Thus, ~40% of identified SPIRE galaxies are likely to be high-redshift (z>~1.4) sources. We discuss the statistical properties of the IRAC-identified SPIRE galaxy sample including far-IR luminosities, dust temperatures, star formation rates, and stellar masses. The majority of our detected galaxies have 10^10^-10^11^L_{sun}_ total IR luminosities and are not intense starbursting galaxies as those found at z~2, but they have a factor of 2-3 above average specific star formation rates compared to near-IR selected galaxy samples.
- ID:
- ivo://CDS.VizieR/J/ApJ/826/171
- Title:
- IR data of debris disk vs metallicity of stars
- Short Name:
- J/ApJ/826/171
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We find that the initial dust masses in planetary debris disks are correlated with the metallicities of their central stars. We compiled a large sample of systems, including Spitzer, the Herschel DUNES and DEBRIS surveys, and WISE debris disk candidates. We also merged 33 metallicity catalogs to provide homogeneous [Fe/H] and {sigma}_[Fe/H]_ values. We analyzed this merged sample, including 222 detected disks (74 warm and 148 cold) around a total of 187 systems (some with multiple components) and 440 disks with only upper limits (125 warm and 315 cold) around a total of 360 systems. The disk dust masses at a common early evolutionary point in time were determined using our numerical disk evolutionary code, evolving a unique model for each of the 662 disks backward to an age of 1Myr. We find that disk-bearing stars seldom have metallicities less than [Fe/H]=-0.2 and that the distribution of warm component masses lacks examples with large mass around stars of low metallicity ([Fe/H]<-0.085). Previous efforts to find a correlation have been largely unsuccessful; the primary improvements supporting our result are (1) basing the study on dust masses, not just infrared excess detections; (2) including upper limits on dust mass in a quantitative way; (3) accounting for the evolution of debris disk excesses as systems age; (4) accounting fully for the range of uncertainties in metallicity measurements; and (5) having a statistically large enough sample.
- ID:
- ivo://CDS.VizieR/J/A+A/559/A79
- Title:
- IRDC APEX/SABOCA observations
- Short Name:
- J/A+A/559/A79
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Infrared-dark clouds (IRDCs) harbor the early phases of cluster and high-mass star formation and are comprised of cold (~20K), dense (n>10^4^cm^-3^) gas. The spectral energy distribution (SED) of IRDCs is dominated by the far-infrared and millimeter wavelength regime, and our initial Herschel study examined IRDCs at the peak of the SED with high angular resolution. Here we present a follow-up study using the SABOCA instrument on APEX which delivers 7.8" angular resolution at 350{mu}m, matching the resolution we achieved with Herschel/PACS, and allowing us to characterize substructure on ~0.1pc scales. Our sample of 11 nearby IRDCs are a mix of filamentary and clumpy morphologies, and the filamentary clouds show significant hierarchical structure, while the clumpy IRDCs exhibit little hierarchical structure. All IRDCs, regardless of morphology, have about 14% of their total mass in small scale core-like structures which roughly follow a trend of constant volume density over all size scales. Out of the 89 protostellar cores we identified in this sample with Herschel, we recover 40 of the brightest and re-fit their SEDs and find their properties agree fairly well with our previous estimates (<T>~19K). We detect a new population of "cold cores" which have no 70{mu}m counterpart, but are 100 and 160{mu}m-bright, with colder temperatures (<T>~16K). This latter population, along with SABOCA-only detections, are predominantly low-mass objects, but their evolutionary diagnostics are consistent with the earliest starless or prestellar phase of cores in IRDCs.
- ID:
- ivo://CDS.VizieR/J/MNRAS/399/1506
- Title:
- IRDC cores in SCUBA Legacy Catalogue
- Short Name:
- J/MNRAS/399/1506
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present an investigation of candidate infrared dark cloud (IRDC) cores as identified by Simon et al. (2006, Cat. J/ApJ/639/227) located within the Submillimetre Common User Bolometer Array (SCUBA) Legacy Catalogue. After applying a uniform noise cut to the catalogue data, we identify 154 IRDC cores that were detected at 850um and 51 cores that were not. We derive column densities for each core from their 8um extinction and find that the IRDCs detected at 850um have higher column densities (a mean of 1.7x10^22^cm^-2^) compared to those cores not detected at 850um (a mean of 1.0x10^22^cm-2).
- ID:
- ivo://CDS.VizieR/J/A+A/606/A133
- Title:
- IRDC G035.39-00.33 NH3 and CCS data cubes
- Short Name:
- J/A+A/606/A133
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Infrared dark clouds represent the earliest stages of high-mass star formation. Detailed observations of their physical conditions on all physical scales are required to improve our understanding of their role in fueling star formation. We investigate the large-scale structure of the IRDC G035.39-00.33, probing the dense gas with the classical ammonia thermometer. This allows us to put reliable constraints on the temperature of the extended, pc-scale dense gas reservoir and to probe the magnitude of its non-thermal motions. Available far-infrared observations can be used in tandem with the observed ammonia emission to estimate the total gas mass contained in G035.39-00.33. We identify a main velocity component as a prominent filament, manifested as an ammonia emission intensity ridge spanning more than 6 pc, consistent with the previous studies on the Northern part of the cloud. A number of additional line-of-sight components are found, and a large-scale linear velocity gradient of ~0.2km/s/pc is found along the ridge of the IRDC. In contrast to the dust temperature map, an ammonia-derived kinetic temperature map, presented for the entirety of the cloud, reveals local temperature enhancements towards the massive protostellar cores. We show that without properly accounting for the line of sight contamination, the dust temperature is 2-3K larger than the gas temperature measured with NH_3_. While both the large-scale kinematics and temperature structure are consistent with that of starless dark filaments, the kinetic gas temperature profile on smaller scales is suggestive of tracing the heating mechanism coincident with the locations of massive protostellar cores.
