- ID:
- ivo://CDS.VizieR/J/ApJ/628/789
- Title:
- IRAS03301+3057 water masers
- Short Name:
- J/ApJ/628/789
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- In this work we present VLA observations of the NH3, CCS, and H2O maser emission at 1cm from the star-forming region B1-IRS (IRAS 03301+3057) with ~5" (=1750AU) of angular resolution. The CCS emission is distributed in three clumps around the central source. These clumps exhibit a velocity gradient from red- to blueshifted velocities toward B1-IRS, probably due to an interaction with the outflow from an embedded protostar.
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- 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.
- 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/ApJ/834/185
- Title:
- IR-bright MSX sources in the SMC with Spitzer/IRS
- Short Name:
- J/ApJ/834/185
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We have used the Infrared Spectrograph (IRS) on the Spitzer Space Telescope to observe stars in the Small Magellanic Cloud (SMC) selected from the Point Source Catalog of the Midcourse Space Experiment (MSX). We concentrate on the dust properties of the oxygen-rich evolved stars. The dust composition has smaller contributions from alumina compared to the Galaxy. This difference may arise from the lower metallicity in the SMC, but it could be a selection effect, as the SMC sample includes more stars that are brighter and thus more massive. The distribution of the SMC stars along the silicate sequence looks more like the Galactic sample of red supergiants than asymptotic giant branch stars (AGBs). While many of the SMC stars are definitively on the AGB, several also show evidence of hot bottom burning. Three of the supergiants show PAH emission at 11.3{mu}m. Two other sources show mixed chemistry, with both carbon-rich and oxygen-rich spectral features. One, MSX SMC 134, may be the first confirmed silicate/carbon star in the SMC. The other, MSX SMC 049, is a candidate post-AGB star. MSX SMC 145, previously considered a candidate OH/IR star, is actually an AGB star with a background galaxy at z=0.16 along the same line of sight. We consider the overall characteristics of all the MSX sources, the most infrared-bright objects in the SMC, in light of the higher sensitivity and resolution of Spitzer, and compare them with the object types expected from the original selection criteria. This population represents what will be seen in more distant galaxies by the upcoming James Webb Space Telescope (JWST). Color-color diagrams generated from the IRS spectra and the mid-infrared filters on JWST show how one can separate evolved stars from young stellar objects (YSOs) and distinguish among different classes of YSOs.
- ID:
- ivo://CDS.VizieR/J/A+A/601/A4
- Title:
- IRC+10216 carbon chains mapped with ALMA
- Short Name:
- J/A+A/601/A4
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Linear carbon chains are common in various types of astronomical molecular sources. Possible formation mechanisms involve both bottom-up and top-down routes. We have carried out a combined observational and modeling study of the formation of carbon chains in the C-star envelope IRC +10216, where the polymerization of acetylene and hydrogen cyanide induced by ultraviolet photons can drive the formation of linear carbon chains of increasing length. We have used ALMA to map the emission of 3 mm rotational lines of the hydrocarbon radicals C_2_H, C_4_H, and C_6_H, and the CN-containing species CN, C_3_N, HC_3_N, and HC_5_N with an angular resolution of 1". The spatial distribution of all these species is a hollow 5-10" wide spherical shell located at a radius of 10-20" from the star, with no appreciable emission close to the star. Our observations resolve the broad shell of carbon chains into thinner subshells that are 1-2" wide and not fully concentric, indicating that the mass-loss process has been discontinuous and not fully isotropic. The radial distributions of the species mapped reveal subtle differences: while the hydrocarbon radicals have very similar radial distributions, the CN-containing species show more diverse distributions, with HC_3_N appearing earlier in the expansion and the radical CN extending later than the rest of the species. The observed morphology can be rationalized by a chemical model in which the growth of polyynes is mainly produced by rapid gas-phase chemical reactions of C_2_H and C_4_H radicals with unsaturated hydrocarbons, while cyanopolyynes are mainly formed from polyynes in gas-phase reactions with CN and C_3_N radicals.
- ID:
- ivo://CDS.VizieR/J/A+A/574/A56
- Title:
- IRC +10216 17.8GHz-26.3GHz spectrum
- Short Name:
- J/A+A/574/A56
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- IRC +10216 is the prototypical carbon star exhibiting an extended molecular circumstellar envelope. Its spectral properties are therefore the template for an entire class of objects. The main goal is to systematically study the 1.3cm spectral line characteristics of IRC +10216. We carried out a spectral line survey with the Effelsberg-100m telescope toward IRC +10216. It covers the frequency range between 17.8GHz and 26.3GHz (K-band). In the circumstellar shell of IRC +10216, we find 78 spectral lines, among which 12 remain unidentified. The identified lines are assigned to 18 different molecules and radicals. A total of 23 lines from species known to exist in this envelope are detected for the first time outside the Solar System and there are additional 20 lines firstly detected in IRC +10216. The potential orgin of U lines is also discussed. Assuming local thermodynamic equilibrium (LTE), we determine rotational temperatures and column densities of 17 detected molecules. Molecular abundances relative to H_2_ are also estimated. A non-LTE analysis of NH_3_ shows that the bulk of its emission arises from the inner envelope with a kinetic temperature of 70+/-20K. Evidence for NH_3_ emitting gas with higher kinetic temperature is also obtained, and potential abundance differences between various ^13^C-bearing isotopologues of HC_5_N are evaluated. Overall, the isotopic ^12^C/^13^C ratio is estimated to be 49+/-9. Finally, a comparison of detected molecules in the 1.3cm range with the dark cloud TMC-1 indicates that silicate bearing molecules are more predominant in IRC +10216.
- ID:
- ivo://CDS.VizieR/J/A+A/606/A74
- Title:
- IRC +10216 13.3GHz-18.5GHz spectrum
- Short Name:
- J/A+A/606/A74
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- A spectral line survey of IRC +10216 between 13.3 and 18.5GHz was carried out using the Shanghai Tian Ma 65 m Radio Telescope (TMRT-65m) with a sensitivity of <7mK. Thirty-five spectral lines of 12 different molecules and radicals were detected in total. Except for SiS, the detected molecules are all carbon-chain molecules, including HC_3_N, HC_5_N, HC_7_N, HC_9_N, C_6_H, C_6_H^-^, C_8_H, SiC_2_, SiC_4_, c-C_3_H_2_, and l-C_5_H. The presence of rich carbon-bearing molecules is consistent with the identity of IRC +10216 as a carbon-rich asymptotic giant branch (AGB) star. The excitation temperatures and column densities of the observed species are derived by assuming a local thermodynamic equilibrium and homogeneous conditions.
- 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/A+A/639/A61
- Title:
- IR continuum, [CII] and [OI] maps of M33
- Short Name:
- J/A+A/639/A61
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- M33 is a gas rich spiral galaxy of the Local Group. Its vicinity allows us to study its interstellar medium (ISM) on linear scales corresponding to the sizes of individual giant molecular clouds. We investigate the relationship between the two major gas cooling lines and the total infrared (TIR) dust continuum. We mapped the emission of gas and dust in M33 using the far-infrared lines of [CII] and [OI](63um) and the total infrared continuum. The line maps were observed with the PACS spectrometer on board the Herschel Space Observatory. These maps have 50pc resolution and form a ~370pc wide stripe along its major axis covering the sites of bright HII regions, but also more quiescent arm and inter-arm regions from the southern arm at 2kpc galacto-centric distance to the south out to 5.7kpc distance to the north. Full-galaxy maps of the continuum emission at 24um from Spitzer/MIPS, and at 70um, 100um, and 160um from Herschel/PACS were combined to obtain a map of the TIR. TIR and [CII] intensities are correlated over more than two orders of magnitude. The range of TIR translates to a range of far ultraviolet (FUV) emission of G_0,obs_~2 to 200 in units of the average Galactic radiation field. The binned [CII]/TIR ratio drops with rising TIR, with large, but decreasing scatter. The contribution of the cold neutral medium to the [CII] emission, as estimated from VLA HI data, is on average only 10%. Fits of modified black bodies (MBBs) to the continuum emission were used to estimate dust mass surface densities and total gas column densities. A correction for possible foreground absorption by cold gas was applied to the [OI] data before comparing it with models of photon dominated regions (PDRs). Most of the ratios of [CII]/[OI] and ([CII]+[OI])/TIR are consistent with two model solutions. The median ratios are consistent with one solution at n~2x10^2^cm^-3^, G_0_~60, and and a second low-FUV solution at n~10^4^cm^-3^, G_0_~1.5. The bulk of the gas along the lines-of-sight is represented by a low-density, high-FUV phase with low beam filling factors ~1. A fraction of the gas may, however, be represented by the second solution.