An all-sky support vector machine selection of<i>WISE</i>YSO candidates

Márton, G.; Tóth, L. V.; Paladini, R.; Kun, M.; Zahorecz, Sarolta; McGehee, P.; Kiss, Cs.

doi:10.1093/mnras/stw398

Cited by 130 publications

(192 citation statements)

References 49 publications

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“…Last, to certify the reliability of the obtained result, we also analyzed in the same manner a more recent catalog of ∼133 980 Class I/II YSOs candidates identified from the ALLWISE catalog (Cutri & et al 2013) based on a vector machine selection (Marton et al 2016). We find that 46 761 of the sources lie in the same area as is covered by the Hi-GAL survey of the inner Galactic plane.…”

Section: Distribution Of Star-forming Sources Related To Ionized Regionsmentioning

confidence: 70%

Spatial distribution of star formation related to ionized regions throughout the inner Galactic plane

Palmeirim

Zavagno

Elia

et al. 2017

A&A

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We present a comprehensive statistical analysis of star-forming objects located in the vicinities of 1360 bubble structures throughout the Galactic plane and their local environments. The compilation of ∼70 000 star-forming sources, found in the proximity of the ionized (Hii) regions and detected in both Hi-GAL and GLIMPSE surveys, provided a broad overview of the different evolutionary stages of star-formation in bubbles, from prestellar objects to more evolved young stellar objects (YSOs). Surface density maps of star-forming objects clearly reveal an evolutionary trend where more evolved star-forming objects (Class II YSO candidates) are found spatially located near the center, while younger star-forming objects are found at the edge of the bubbles. We derived dynamic ages for a subsample of 182 H ii regions for which kinematic distances and radio continuum flux measurements were available. We detect approximately 80% more star-forming sources per unit area in the direction of bubbles than in the surrounding fields. We estimate the clump formation efficiency (CFE) of Hi-GAL clumps in the direction of the shell of the bubbles to be ∼15%, around twice the value of the CFE in fields that are not affected by feedback effects. We find that the higher values of CFE are mostly due to the higher CFE of protostellar clumps, in particular in younger bubbles, whose density of the bubble shells is higher. We argue that the formation rate from prestellar to protostellar phase is probably higher during the early stages of the (H ii ) bubble expansion. Furthermore, we also find a higher fraction of massive YSOs (MYSOs) in bubbles at the early stages of expansion (<2 Myr) than older bubbles. Evaluation of the fragmentation time inside the shell of bubbles advocates the preexistence of clumps in the medium before the bubble expansion in order to explain the formation of MYSOs in the youngest H ii regions (<1 Myr), as supported by numerical simulations. Approximately 23% of the Hi-GAL clumps are found located in the direction of a bubble, with 15% for prestellar clumps and 41% for protostellar clumps. We argue that the high fraction of protostellar clumps may be due to the acceleration of the star-formation process cause by the feedback of the (Hii) bubbles.

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Section: Distribution Of Star-forming Sources Related To Ionized Regionsmentioning

confidence: 70%

Spatial distribution of star formation related to ionized regions throughout the inner Galactic plane

Palmeirim

Zavagno

Elia

et al. 2017

A&A

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“…We examined the spatial distribution of young stellar objects (YSOs) using the catalogue of YSO candidates of Marton et al (2016) that is based on the analysis of 2MASS (Skrutskie et al 2006) and WISE (Wright et al 2010) data . Figure 8 shows the surface density as a function of the distance from the centre of the SCUBA-2 fields.…”

Section: Young Stellar Objectsmentioning

confidence: 99%

Herscheland SCUBA-2 observations of dust emission in a sample ofPlanckcold clumps

Juvela

Pattle

et al. 2018

A&A

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Context. Analysis of all-sky Planck submillimetre observations and the IRAS 100 µm data has led to the detection of a population of Galactic cold clumps. The clumps can be used to study star formation and dust properties in a wide range of Galactic environments. Aims. Our aim is to measure dust spectral energy distribution (SED) variations as a function of the spatial scale and the wavelength. Methods. We examine the SEDs at large scales using IRAS, Planck, and Herschel data. At smaller scales, we compare with JCMT/SCUBA-2 850 µm maps with Herschel data that are filtered using the SCUBA-2 pipeline. Clumps are extracted using the Fellwalker method and their spectra are modelled as modified blackbody functions. Results. According to IRAS and Planck data, most fields have dust colour temperatures T C ∼ 14 − 18 K and opacity spectral index values of β = 1.5 − 1.9. The clumps/cores identified in SCUBA-2 maps have T ∼ 13 K and similar β values. There are some indications of the dust emission spectrum becoming flatter at wavelengths longer than 500 µm. In fits involving Planck data, the significance is limited by the uncertainty of the corrections for CO line contamination. The fits to the SPIRE data give a median β value slightly above 1.8. In the joint SPIRE and SCUBA-2 850 µm fits the value decreases to β ∼1.6. Most of the observed T -β anticorrelation can be explained by noise. Conclusions. The typical submillimetre opacity spectral index β of cold clumps is found to be ∼1.7. This is above the values of diffuse clouds but lower than in some previous studies of dense clumps. There is only tentative evidence of T -β anticorrelation and β decreasing at millimetre wavelengths.

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“…The all-sky YSO candidate catalogs of Tóth et al (2014) and Marton et al (2016) can be used to search for low-and intermediate-mass star formation. We find that four of our ECC clumps without 70 µm point sources show AKARI or WISE YSOs.…”

Section: Clump Categories Based On Hi-gal 70 µM Datamentioning

confidence: 99%

Physical properties of GalacticPlanckcold cores revealed by the Hi-GAL survey

Zahorecz

Jiménez-Serra

Wang

et al. 2016

A&A

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Context. Previous studies of the initial conditions of massive star and star cluster formation have mainly targeted infrared-dark clouds (or IRDCs) toward the inner Galaxy. This is because IRDCs were first detected in absorption against the bright mid-infrared (IR) background of the inner Galaxy, requiring a favorable location to be observed. By selection, IRDCs therefore represent only a fraction of the Galactic clouds capable of forming massive stars and star clusters. Owing their low dust temperatures, however, IRDCs are bright in the far-IR and millimeter and, thus, observations at these wavelengths have the potential to provide a complete sample of star-forming massive clouds across the Galaxy. Aims. Our aim is to identify the clouds at the initial conditions of massive star and star cluster formation across the Galaxy and compare their physical properties as a function of Galactic longitude and Galactocentric distance. Methods. We have examined the physical properties of a homogeneous Galactic cold core sample obtained with the Planck satellite across the Galactic plane. With the use of Herschel Hi-GAL observations, we characterized the internal structure of the most reliable Galactic cold clumps within the Early Cold Core (ECC) Planck catalog. By using background-subtracted Herschel images, we derived the H 2 column density and dust temperature maps for 48 Planck clumps covered by the Herschel Hi-GAL survey. We calculated and analyzed the basic physical parameters (size, mass, and average dust temperature) of these clumps as a function of location within the Galaxy. We also compared these properties with the empirical relation for massive star formation previously derived. Results. Most of the Planck clumps contain signs of star formation. About 25% of the clumps are massive enough to form highmass stars and star clusters since they exceed the empirical threshold for massive star formation. Planck clumps toward the Galactic center region show higher peak column densities and higher average dust temperatures than those of the clumps in the outer Galaxy. Although we only have seven clumps without associated YSOs, the Hi-GAL data show no apparent differences in the properties of Planck cold clumps with and without star formation.

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An all-sky support vector machine selection ofWISEYSO candidates

Cited by 130 publications

References 49 publications

Spatial distribution of star formation related to ionized regions throughout the inner Galactic plane

Spatial distribution of star formation related to ionized regions throughout the inner Galactic plane

Herscheland SCUBA-2 observations of dust emission in a sample ofPlanckcold clumps

Physical properties of GalacticPlanckcold cores revealed by the Hi-GAL survey

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