The SPECFIND V2.0 catalogue of radio cross-identifications and spectra

Vollmer, B.; Gassmann, B.; Derriére, S.; Boch, T.; Louys, Mireille; Bonnarel, F.; Dubois, P.; Genova, F.; Ochsenbein, F.

doi:10.1051/0004-6361/200913460

Cited by 71 publications

(80 citation statements)

References 81 publications

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“…Another plausible reason could be the high resolution of GMRT data which might have filtered out the extended emission. A low resolution survey of the region by Vollmer et al (2010) at 4800 MHz gives an integrated flux of 4.3 Jy, which yields NLyc ∼ 10 49 , suggesting an O6 V spectral type for the ionizing source, which agrees well with the spectral class estimated by previous studies. The GMRT radio data reveals four peaks which may be clumps/compact H ii regions, marked as A, B, C, and D in Fig.…”

Section: Emission From Ionized Gas In the S311 Regionsupporting

confidence: 87%

A multiwavelength investigation of the H ii region S311: young stellar population and star formation

Yadav

Pandey

Sharma

et al. 2016

Mon. Not. R. Astron. Soc.

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We present a multiwavelength investigation of the young stellar population and star formation activities around the H ii region Sharpless 311. Using our deep near-infrared observations and archival Spitzer-IRAC observations, we have detected a total of 125 young stellar objects (YSOs) in an area of ∼86 arcmin 2 . The YSOs sample include 8 Class I and 117 Class II candidate YSOs. The mass completeness of the identified YSOs sample is estimated to be 1.0 M . The ages and masses of the majority of the candidate YSOs are estimated to be in the range of ∼0.1−5 Myr and ∼0.3−6 M , respectively. The 8 µm image of S311 displays an approximately spherical cavity around the ionizing source which is possibly created due to the expansion of the H ii region. The spatial distribution of the candidate YSOs reveals that a significant number of them are distributed systematically along the 8 µm emission with a majority clustered around the eastern border of the H ii region. Four clumps/compact H ii regions are detected in the radio continuum observations at 1280 MHz, which might have been formed during the expansion of the H ii region. The estimated dynamical age of the region, main-sequence lifetime of the ionizing source, the spatial distribution and ages of the candidate YSOs indicate triggered star formation in the complex.

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Section: Emission From Ionized Gas In the S311 Regionsupporting

confidence: 87%

A multiwavelength investigation of the H ii region S311: young stellar population and star formation

Yadav

Pandey

Sharma

et al. 2016

Mon. Not. R. Astron. Soc.

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“…We added two dust continuum flux measurements from the LWS spectrum at 43 and 115 μm of 4 × 10 −18 and 5 × 10 −19 W cm −2 μm −1 respectively (aperture correction factors have not yet been applied to these values). We also used two radio continuum flux densities at 4850 and 1400 MHz of 360 and 440 mJy respectively, which are averages of the data collected by Vollmer et al (2010). For the angular diameter we used 76 (Liu et al 2004).…”

Section: Appendix B: Photometrymentioning

confidence: 99%

Herschelimages of NGC 6720: H₂formation on dust grains

Hoof

Steene

Barlow

et al. 2010

A&A

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Herschel PACS and SPIRE images have been obtained of NGC 6720 (the Ring nebula). This is an evolved planetary nebula with a central star that is currently on the cooling track, due to which the outer parts of the nebula are recombining. From the PACS and SPIRE images we conclude that there is a striking resemblance between the dust distribution and the H 2 emission, which appears to be observational evidence that H 2 forms on grain surfaces. We have developed a photoionization model of the nebula with the Cloudy code which we used to determine the physical conditions of the dust and investigate possible formation scenarios for the H 2 . We conclude that the most plausible scenario is that the H 2 resides in high density knots which were formed after the recombination of the gas started when the central star entered the cooling track. Hydrodynamical instabilities due to the unusually low temperature of the recombining gas are proposed as a mechanism for forming the knots. H 2 formation in the knots is expected to be substantial after the central star underwent a strong drop in luminosity about one to two thousand years ago, and may still be ongoing at this moment, depending on the density of the knots and the properties of the grains in the knots.

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“…Using catalogues at various frequencies from different telescopes with large differences in angular resolution to calculate source properties, such as their spectra, may be a difficult exercise in practice. Vollmer et al (2010) present SPECFIND V2.0 (accessible via the CDS/Strasbourg), which is a systematic approach to deriving about 65 × 10 3 spectra of radio sources. They show examples for the general large scatter in published flux densities, but also discuss methods for deriving reliable spectra.…”

Section: Discussionmentioning

confidence: 99%

A Sino-Germanλ6 cm polarisation survey of the Galactic plane

Reich

Sun

Reich

et al. 2013

A&A

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Aims. Information of small-diameter sources is extracted from the Sino-German λ6 cm polarisation survey of the Galactic plane carried out with the Urumqi 25-m telescope. Methods. We performed two-dimensional elliptical Gaussian fits to the λ6 cm maps to obtain a list of sources with total-intensity and polarised flux densities. Results. The source list contains 3832 sources with a fitted diameter smaller than 16 and a peak flux density exceeding 30 mJy, so about 5× the rms noise, of the total-intensity data. The cumulative source count indicates completeness for flux densities exceeding about 60 mJy. We identify 125 linearly polarised sources at λ6 cm with a peak polarisation flux density greater than 10 mJy, so about 3× the rms noise of the polarised-intensity data. Conclusions. Despite lacking compact steep spectrum sources, the λ6 cm catalogue lists about 20% more sources than the Effelsberg λ21 cm source catalogue at the same angular resolution and for the same area. Most of the faint λ6 cm sources must have a flat spectrum and are either H ii regions or extragalactic. When compared with the Green Bank λ6 cm (GB6) catalogue, we obtain higher flux densities for a number of extended sources with complex structures. Polarised λ6 cm sources density are uniformly distributed in Galactic latitude. Their number density decreases towards the inner Galaxy. More than 80% of the polarised sources are most likely extragalactic. With a few exceptions, the sources have a higher percentage polarisation at λ6 cm than at λ21 cm. Depolarisation seems to occur mostly within the sources with a minor contribution from the Galactic foreground emission.

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The SPECFIND V2.0 catalogue of radio cross-identifications and spectra

Cited by 71 publications

References 81 publications

A multiwavelength investigation of the H ii region S311: young stellar population and star formation

A multiwavelength investigation of the H ii region S311: young stellar population and star formation

Herschelimages of NGC 6720: H₂formation on dust grains

A Sino-Germanλ6 cm polarisation survey of the Galactic plane

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The SPECFIND V2.0 catalogue of radio cross-identifications and spectra

Cited by 71 publications

References 81 publications

A multiwavelength investigation of the H ii region S311: young stellar population and star formation

A multiwavelength investigation of the H ii region S311: young stellar population and star formation

Herschelimages of NGC 6720: H2formation on dust grains

A Sino-Germanλ6 cm polarisation survey of the Galactic plane

Contact Info

Product

Resources

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Herschelimages of NGC 6720: H₂formation on dust grains