- 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).
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Search Results
- 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.
- ID:
- ivo://CDS.VizieR/J/ApJ/694/546
- Title:
- IR dust bubbles. II. YSOs model parameters
- Short Name:
- J/ApJ/694/546
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present an analysis of late-O/early-B-powered, parsec-sized bubbles and associated star formation using Two Micron All Sky Survey, GLIMPSE, MIPSGAL, and MAGPIS surveys. Three bubbles were selected from the Churchwell et al. catalog (2007, Cat. J/ApJ/670/428). We confirm that the structure identified in Watson et al. (2008ApJ...681.1341W) holds in less energetic bubbles, i.e., a photodissociated region, identified by 8um emission due to polycyclic aromatic hydrocarbons surrounding hot dust, identified by 24um emission and ionized gas, and identified by 20cm continuum. We estimate the dynamical age of two bubbles by comparing bubble sizes to numerical models of Hosokawa and Inutsuka. We also identify and analyze candidate young stellar objects using spectral energy distribution (SED) fitting and identify sites of possible triggered star formation. Lastly, we identify likely ionizing sources for two sources based on SED fitting.
- ID:
- ivo://CDS.VizieR/J/MNRAS/437/391
- Title:
- IR excess in Sun-like stars observed by WISE
- Short Name:
- J/MNRAS/437/391
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the results of a search for infrared-excess (IR-excess) candidates in a comprehensive (29000 stars) magnitude-limited sample of dwarf stars, spanning the spectral range F2-K0, and brighter than V=15mag. We searched the sample within the WISE all sky survey data base for objects within 1 arcsec of the coordinates provided by the SIMBAD data base, and found over 9000 sources detected in all WISE bands. The sample excludes objects that are flagged as extended sources and those images that are affected by various optical artefacts. For each detected object, we compared the observed W4/W2 (22{mu}m/4.6{mu}m) flux ratio with the expected photospheric value and identified 197 excess candidates at 3{sigma}. For the vast majority of candidates, the results of this analysis represent the first reported evidence of an IR excess. Through the comparison with a simple blackbody emission model, we derive estimates of the dust temperature, as well as of the dust fractional luminosities. For more than 80 percent of the sample, this temperature is higher than 120K, suggesting the presence of warm circumstellar dust. Complementary observations at longer wavelengths (far-IR and submillimetre) are required for better characterizing and explaining the origin of this emission.
- ID:
- ivo://CDS.VizieR/J/ApJ/658/1264
- Title:
- IR-excess sources in GLIMPSE and MSX
- Short Name:
- J/ApJ/658/1264
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We have identified 230 Tycho-2 Spectral Catalog stars that exhibit 8um mid-IR extraphotospheric excesses in the MSX and Spitzer GLIMPSE surveys. Of these, 183 are either OB stars earlier than B8 in which the excess plausibly arises from a thermal bremsstrahlung component or evolved stars in which the excess may be explained by an atmospheric dust component. The remaining 47 stars have spectral classifications B8 or later and appear to be main-sequence or late pre-main-sequence objects harboring circumstellar disks. Six of the 47 stars exhibit multiple signatures characteristic of pre-main-sequence circumstellar disks, including emission lines, near-IR K-band excesses, and X-ray emission. Approximately one-third of the remaining 41 sources have emission lines suggesting relative youth. We modeled the excesses in 26 stars having two or more measurements in excess of the expected photospheres as single-component blackbodies.
- ID:
- ivo://CDS.VizieR/J/ApJ/555/932
- Title:
- IR fluxes of solar-type stars
- Short Name:
- J/ApJ/555/932
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Using ISO-ISOPHOT, we carried out a survey of almost 150 stars to search for evidence of emission from dust orbiting young main-sequence stars, both in clusters and isolated systems. Over half of the detections are new examples of dusty stellar systems and demonstrate that such dust can be detected around numerous stars older than a few times 10^6^yr. Fluxes at 60 and either 90 or 100{mu}m or the new excess sources together with improved fluxes for a number of IRAS-identified sources are presented. Analysis of the excess luminosity relative to the stellar photosphere shows a systematic decline of this excess with stellar age consistent with a power-law index of -2.
- ID:
- ivo://CDS.VizieR/J/ApJ/900/104
- Title:
- IR high-res. sp. of hot cores of AFGL2591 & AFGL2136
- Short Name:
- J/ApJ/900/104
- Date:
- 21 Mar 2022 09:36:08
- Publisher:
- CDS
- Description:
- We have performed a high-resolution 4-13{mu}m spectral survey of the hot molecular gas associated with the massive protostars AFGL 2591 and AFGL 2136, utilizing the Echelon Cross Echelle Spectrograph (EXES) on board the Stratospheric Observatory for Infrared Astronomy, and the iSHELL instrument and Texas EchelonCross Echelle Spectrograph (TEXES) on the NASA Infrared Telescope Facility (IRTF). Here we present the results of this survey with analysis of CO, HCN, C2H2, NH3, and CS, deriving the physical conditions for each species. Also from the IRTF, iSHELL data at 3{mu}m for AFGL 2591 are presented that show HCN and C2H2 in emission. In the EXES and TEXES data, all species are detected in absorption, and temperatures and abundances are found to be high (600K and 10^-6^, respectively). Differences of up to an order of magnitude in the abundances of transitions that trace the same ground-state level are measured for HCN and C2H2. The mid-infrared continuum is known to originate in a disk, hence we attribute the infrared absorption to arise in the photosphere of the disk. As absorption lines require an outwardly decreasing temperature gradient, we conclude that the disk is heated in the midplane by viscous heating due to accretion. We attribute the near-IR emission lines to scattering by molecules in the upper layers of the disk photosphere. The absorption lines trace the disk properties at 50 au where high-temperature gas-phase chemistry is taking place. Abundances are consistent with chemical models of the inner disk of Herbig disks.
- ID:
- ivo://CDS.VizieR/J/ApJ/723/895
- Title:
- IR luminosities and aromatic features of 5MUSES
- Short Name:
- J/ApJ/723/895
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We study a 24um selected sample of 330 galaxies observed with the infrared spectrograph for the 5mJy Unbiased Spitzer Extragalactic Survey (5MUSES). We estimate accurate total infrared luminosities by combining mid-IR spectroscopy and mid-to-far infrared photometry, and by utilizing new empirical spectral templates from Spitzer data. The infrared luminosities of this sample range mostly from 10^9^L_{sun}_ to 10^13.5^L_{sun}_, with 83% in the range 10^10^L_{sun}_<L_IR_<10^12^L_{sun}_. The redshifts range from 0.008 to 4.27, with a median of 0.144. The equivalent widths of the 6.2um aromatic feature have a bimodal distribution, probably related to selection effects. We use the 6.2um polycyclic aromatic hydrocarbon equivalent width (PAH EW) to classify our objects as starburst (SB)-dominated (44%), SB-AGN composite (22%), and active galactic nucleus (AGN)-dominated (34%). The high EW objects (SB-dominated) tend to have steeper mid-IR to far-IR spectral slopes and lower LIR and redshifts.
- ID:
- ivo://CDS.VizieR/J/ApJ/761/184
- Title:
- IR luminosities for dusty AGNs and QSOs
- Short Name:
- J/ApJ/761/184
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Mid-infrared spectroscopic measurements from the Infrared Spectrometer (IRS) on Spitzer are given for 125 hard X-ray active galactic nuclei (AGNs; 14-195keV) from the Swift Burst Alert Telescope (BAT) sample and for 32 AGNs with black hole masses (BHMs) from reverberation mapping. The 9.7{mu}m silicate feature in emission or absorption defines an infrared AGN classification describing whether AGNs are observed through dust clouds, indicating that 55% of the BAT AGNs are observed through dust. The 100 most luminous type 1 quasars as measured in {nu}L_{nu}_(7.8{mu}m) are found by comparing Sloan Digital Sky Survey (SDSS) optically discovered quasars with photometry at 22{mu}m from the Wide-Field Infrared Survey Explorer (WISE), scaled to rest frame 7.8{mu}m using an empirical template determined from IRS spectra. The most luminous SDSS/WISE quasars have the same maximum infrared luminosities for all 1.5<z<5, reaching total infrared luminosity L_IR_=10^14.4^L_{sun}_. Comparing with dust-obscured galaxies from Spitzer and WISE surveys, we find no evidence of hyperluminous obscured quasars whose maximum infrared luminosities exceed the maximum infrared luminosities of optically discovered quasars. Bolometric luminosities L_bol_ estimated from rest-frame optical or ultraviolet luminosities are compared to L_IR_. For the local AGN, the median logL_IR_/L_bol_=-0.35, consistent with a covering factor of 45% for the absorbing dust clouds. For the SDSS/WISE quasars, the median logL_IR_/L_bol_=0.1, with extremes indicating that ultraviolet-derived L_bol_ can be seriously underestimated even for type 1 quasars.
- ID:
- ivo://CDS.VizieR/J/A+A/375/1
- Title:
- IR observations of Chandra Deep Field + HDF-South
- Short Name:
- J/A+A/375/1
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present near-IR (J and Ks) number counts and colors of galaxies detected in deep VLT-ISAAC images centered on the Chandra Deep Field (03h 32min 16s, -27{deg} 47' 25") and on the Hubble Deep Field-South. (22h 32min 55s, -60{deg} 33' 08"). The data have been obtained with the ISAAC infrared imager/spectrometer at the ESO VLT-UT1 telescope on several nights from September to December 1999 (seeing conditions around 0.7arcsec). The limiting surface brightness (1 sigma) obtained is 24.5mag/arcsec^2^ in J and 22mag/arcsec^2^ in Ks.
