- ID:
- ivo://CDS.VizieR/J/A+AS/101/513
- Title:
- JHKLM photometry of C stars
- Short Name:
- J/A+AS/101/513
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present J H K L M photometry for 25 Carbon stars, and 450, 600, 800 and 1100 {mu}m for 12 carbon stars and the S-star W Aql. Carbon stars reside on a different part of the [12-25], [K-L] diagram than O-rich stars. Our work confirms earlier observations and shows this relation to hold up at least [K-L] ~ 8mag.
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Search Results
- ID:
- ivo://CDS.VizieR/J/MNRAS/359/2
- Title:
- JHK photometry in G173.58+2.45
- Short Name:
- J/MNRAS/359/2
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a multi-epoch infrared photometric study of the intermediate-mass star-forming region G173.58+2.45. Photometric observations are obtained using the near-infrared JHKL'M' filters and narrow-band filters centred at the wavelengths of the H_2_(1-0)S(1)(2.122um) and [FeII](1.644um) lines. The H2 image shows molecular emission from shocked gas, implying the presence of multiple star formation and associated outflow activity. We see evidence for several collimated outflows.
- ID:
- ivo://CDS.VizieR/J/ApJ/602/850
- Title:
- JHK' photometry near IRAS 18507+0121
- Short Name:
- J/ApJ/602/850
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We have observed the massive star-forming region IRAS 18507+0121 at millimeter wavelengths in 3mm continuum emission, H^13^CO+ (J=1-0) and SiO (v=0,J=2-1) line emission, and at near-infrared (NIR) wavelengths between 1.2 and 2.1{mu}m. Two compact molecular cores are detected: one north and one south, separated by ~40". The northern molecular core contains a newly discovered, deeply embedded, B2 protostar surrounded by several hundred solar masses of warm gas and dust, G34.4+0.23 MM. Based on the presence of warm dust emission and the lack of detection at NIR wavelengths, we suggest that G34.4+0.23 MM may represent the relatively rare discovery of a massive protostar (e.g., analogous to a low-mass "Class 0" protostar). The southern molecular core is associated with an NIR cluster of young stars and an ultracompact HII region, G34.4+0.23, with a central B0.5 star. The fraction of NIR stars with excess infrared emission indicative of circumstellar material is greater than 50%, which suggests an upper limit on the age of the IRAS 18507+0121 star-forming region of 3Myr.
- ID:
- ivo://CDS.VizieR/J/MNRAS/377/430
- Title:
- Jodrell Bank Flat-spectrum radio sample
- Short Name:
- J/MNRAS/377/430
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the selection of the Jodrell Bank Flat-spectrum (JBF) radio source sample, which is designed to reduce the uncertainties in the Cosmic Lens All-Sky Survey (CLASS) gravitational lensing statistics arising from the lack of knowledge about the parent population luminosity function. From observations at 4.86GHz with the Very Large Array, we have selected a sample of 117 flat-spectrum radio sources with flux densities greater than 5mJy. These sources were selected in a similar manner to the CLASS complete sample and are therefore representative of the parent population at low flux densities. The vast majority (~90 per cent) of the JBF sample are found to be compact on the arcsec scales probed here and show little evidence of any extended radio jet emission. Using the JBF and CLASS complete samples, we find the differential number counts slope of the parent population above and below the CLASS 30-mJy flux density limit to be 2.07+/-0.02 and 1.96+/-0.12, respectively.
735. JVLA images of W51A
- ID:
- ivo://CDS.VizieR/J/A+A/595/A27
- Title:
- JVLA images of W51A
- Short Name:
- J/A+A/595/A27
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present new JVLA observations of the high-mass cluster-forming region W51A from 2 to 16GHz with resolution {theta}_fwhm_~~0.3-0.5". The data reveal a wealth of observational results: (1) Currently-forming, very massive (proto-O) stars are traced by o-H_2_CO 2_1,1_-2_1,2_ emission, suggesting that this line can be used efficiently as a massive protostar tracer. (2) There is a spatially distributed population of <~mJy continuum sources, including hypercompact HII regions and candidate colliding wind binaries, in and around the W51 proto-clusters. (3) There are two clearly detected protoclusters, W51e and W51 IRS2, that are gas-rich but may have most of their mass in stars within their inner <~0.05pc. The majority of the bolometric luminosity in W51 most likely comes from a third population of OB stars between these clusters. The presence of a substantial population of exposed O-stars coincident with a population of still-forming massive stars, along with a direct measurement of the low mass loss rate via ionized gas outflow from W51 IRS2, together imply that feedback is ineffective at halting star formation in massive protoclusters. Instead, feedback may shut off the large-scale accretion of diffuse gas onto the W51 protoclusters, implying that they are evolving towards a state of gas exhaustion rather than gas expulsion. Recent theoretical models predict gas exhaustion to be a necessary step in the formation of gravitationally bound stellar clusters, and our results provide an observational validation of this process.
- ID:
- ivo://CDS.VizieR/J/ApJ/871/215
- Title:
- JVLA rotation measures of Smith cloud bckg sources
- Short Name:
- J/ApJ/871/215
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The Smith Cloud is a high-velocity cloud with an orbit suggesting it has made at least one passage through the Milky Way disk. A magnetic field found around this cloud has been thought to provide extra stability as it passes through the Galactic halo. We use the Karl G. Jansky Very Large Array to measure Faraday rotation measures (RMs) toward 1105 extragalactic background point sources behind and next to the Smith Cloud to constrain the detailed geometry and strength of its magnetic field. The RM pattern across the cloud gives the detailed morphology of the magnetic field structure, which indicates a field draped over the ionized gas and compressed at the head of the cloud. We constrain the peak line-of-sight magnetic field strength to >~+5{mu}G and create a model of the magnetic field to demonstrate that a draped configuration can qualitatively explain the morphology of the observed RMs.
- ID:
- ivo://CDS.VizieR/J/ApJ/810/L9
- Title:
- 1.5Jy MOJAVE AGN sample and 3FGL data
- Short Name:
- J/ApJ/810/L9
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We use the complete MOJAVE 1.5Jy sample of active galactic nuclei (AGNs) to examine the gamma-ray detection statistics of the brightest radio-loud blazars in the northern sky. We find that 23% of these AGNs were not detected above 0.1GeV by the Fermi-LAT during the four-year 3FGL catalog period partly because of an instrumental selection effect and partly due to their lower Doppler boosting factors. Blazars with synchrotron peaks in their spectral energy distributions located below 10^13.4^Hz also tend to have high-energy peaks that lie below the 0.1GeV threshold of the LAT, and are thus less likely to be detected by Fermi. The non-detected AGNs in the 1.5Jy sample also have significantly lower 15GHz radio modulation indices and apparent jet speeds, indicating that they have lower than average Doppler factors. Since the effective amount of relativistic Doppler boosting is enhanced in gamma-rays (particularly in the case of external inverse-Compton scattering), this makes them less likely to appear in the 3FGL catalog. Based on their observed properties, we have identified several bright radio-selected blazars that are strong candidates for future detection by Fermi.
- ID:
- ivo://CDS.VizieR/J/A+A/596/A106
- Title:
- 1Jy northern AGN sample
- Short Name:
- J/A+A/596/A106
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Continuum spectra covering centimetre to submillimetre wavelengths are presented for a northern sample of 104 extragalactic radio sources, mainly active galactic nuclei, based on four-epoch Planck data. The nine Planck frequencies, from 30 to 857GHz, are complemented by a set of simultaneous ground-based radio observations between 1.1 and 37GHz. The single-survey Planck data confirm that the flattest high-frequency radio spectral indices are close to zero, indicating that the original accelerated electron energy spectrum is much harder than commonly thought, with power-law index around 1.5 instead of the canonical 2.5. The radio spectra peak at high frequencies and exhibit a variety of shapes. For a small set of low-z sources, we find a spectral upturn at high frequencies, indicating the presence of intrinsic cold dust. Variability can generally be approximated by achromatic variations, while sources with clear signatures of evolving shocks appear to be limited to the strongest outbursts.
- ID:
- ivo://CDS.VizieR/J/other/PASA/26.439
- Title:
- K-band images of star-forming regions
- Short Name:
- J/other/PASA/26.
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present deep, wide-field, Ks-band (2.14-micron) images towards 87 southern massive star formation regions traced by methanol maser emission. Using point-spread function fitting, we generate 2.14-micron point source catalogues (PSCs) towards each of the regions. For the regions between 10{deg}<l<350{deg} and |b|<1, we match the 2.14-micron sources with the GLIMPSE point source catalogue to generate a combined 2.14- to 8.0-micron point source catalogue. We provide this data for the astronomical community to utilise in studies of the stellar content of embedded clusters.
- ID:
- ivo://CDS.VizieR/J/AJ/143/35
- Title:
- KCAL VERA 22 GHz calibrator survey
- Short Name:
- J/AJ/143/35
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We observed at 22GHz with the VLBI array VERA a sample of 1536 sources with correlated flux densities brighter than 200mJy at 8GHz. One half of target sources has been detected. The detection limit was around 200mJy. We derived the correlated flux densities of 877 detected sources in three ranges of projected baseline lengths. The objective of these observations was to determine the suitability of given sources as phase calibrators for dual-beam and phase-referencing observations at high frequencies. Preliminary results indicate that the number of compact extragalactic sources at 22GHz brighter than a given correlated flux density level is twice less than at 8GHz.