UWISH2 - the UKIRT Widefield Infrared Survey for H2

Froebrich, D.; Davis, C. J.; Ioannidis, G.; Gledhill, Tim; Takami, M.; Chrysostomou, A.; Drew, J. E.; Eislöffel, J.; Gosling, Amanda; Gredel, R.; Hatchell, Jennifer; Hodapp, Klaus W.; Kumar, M. S. N.; Lucas, P. W.; Matthews, H. E.; Rawlings, Mark G.; Smith, Michael D.; Stecklum, B.; Varricatt, W. P.; Lee, H. T.; Teixeira, P. S.; Aspin, C.; Khanzadyan, T.; Karr, J.; Kim, Hyun-Jeong; Koo, B. C.; Lee, J.J; Lee, Y.H; Magakian, T. Yu.; Movsessian, T. A.; Nikogossian, E. H.; Pyo, Tae‐Soo; Stanke, T.

doi:10.1111/j.1365-2966.2010.18149.x

Cited by 72 publications

(61 citation statements)

References 92 publications

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“…Our analysis uses data from the UKIRT Widefield Infrared Survey for H2 by Froebrich et al (2011) and its extension towards the Cygnus X and Cassiopeia/Auriga regions discussed in Froebrich et al (2015). All images are taken with the Wide Field Camera (Casali et al 2007) at the UK Infra-Red Telescope.…”

Section: Uwish2 Datamentioning

confidence: 99%

“…by Walawender et al (2005), Hatchell et al (2007), Davis et al (2009) and Khanzadyan et al (2012). In order to establish a truly unbiased sample of jets and outflows from young stars in the Galaxy, not restricted to nearby, mostly low-mass star forming regions, the UKIRT Widefield Infrared Survey for H2 (UWISH2) was conducted by Froebrich et al (2011). In this series of papers we are analysing in detail the identified jets and outflows from young stars in this survey as Molecular Hydrogen emission-line Objects (MHOs) defined in Davis et al (2010).…”

Section: Introductionmentioning

confidence: 99%

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YSO jets in the Galactic plane from UWISH2 – III. Jets and outflows in Cassiopeia and Auriga

Froebrich

Makin

2016

Mon. Not. R. Astron. Soc.

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We present the analysis of 35.5 square degrees of images in the 1 -0 S(1) line of H 2 from the UK Widefield Infrared Survey for H 2 (UWISH2) towards Cassiopeia and Auriga. We have identified 98 Molecular Hydrogen emission-line Objects (MHOs) driven by Young Stellar Objects, 60 % of which are bipolar outflows and all are new discoveries. We estimate that the UWISH2 extended emission object catalogue contains fewer than 2 % false positives and is complete at the 95 % level for jets and outflows brighter than the UWISH2 detection limit. We identified reliable driving source candidates for three quarters of the detected outflows, 40 % of which are associated with groups and clusters of stars. The driving source candidates are 20 % protostars, the remainder are CTTSs. We also identified 15 new star cluster candidates near MHOs in the survey area.We find that the typical outflow identified in the sample has the following characteristics: the position angles are randomly orientated; bipolar outflows are straight within a few degrees; the two lobes are slightly asymmetrical in length and brightness; the length and brightness of the lobes are not correlated; typical time gaps between major ejections of material are 1 -3 kyr, hence FU-Ori or EX-Ori eruptions are most likely not the cause of these, but we suggest MNors as a possible source. Furthermore, we find that outflow lobe length distributions are statistically different from the widely used total length distributions. There are a larger than expected number of bright outflows indicating that the flux distribution does not follow a power law.

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Section: Uwish2 Datamentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

YSO jets in the Galactic plane from UWISH2 – III. Jets and outflows in Cassiopeia and Auriga

Froebrich

Makin

2016

Mon. Not. R. Astron. Soc.

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“…For this purpose, we retrieved the UWISH2 image of the H 2 2.12 μm line (Froebrich et al 2011), shown in Fig. 15.…”

Section: Precessing Jetmentioning

confidence: 99%

A necklace of dense cores in the high-mass star forming region G35.20−0.74 N: ALMA observations

Sánchez-Monge

Beltrán

Cesaroni

et al. 2014

A&A

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Context. The formation process of high-mass stars (with masses >8 M ) is still poorly understood, and represents a challenge from both the theoretical and observational points of view. The advent of the Atacama Large Millimeter Array (ALMA) is expected to provide observational evidence to better constrain the theoretical scenarios. Aims. The present study aims at characterizing the high-mass star forming region G35.20−0.74 N, which is found associated with at least one massive outflow and contains multiple dense cores, one of them recently found associated with a Keplerian rotating disk. Methods. We used the radio-interferometer ALMA to observe the G35.20−0.74 N region in the submillimeter continuum and line emission at 350 GHz. The observed frequency range covers tracers of dense gas (e.g., H 13 CO + , C 17 O), molecular outflows (e.g., SiO), and hot cores (e.g., CH 3 CN, CH 3 OH). These observations were complemented with infrared and centimeter data. Results. The ALMA 870 μm continuum emission map reveals an elongated dust structure (∼0.15 pc long and ∼0.013 pc wide; full width at half maximum) perpendicular to the large-scale molecular outflow detected in the region, and fragmented into a number of cores with masses ∼1-10 M and sizes ∼1600 AU (spatial resolution ∼960 AU). The cores appear regularly spaced with a separation of ∼0.023 pc. The emission of dense gas tracers such as H 13 CO + or C 17 O is extended and coincident with the dust elongated structure. The three strongest dust cores show emission of complex organic molecules characteristic of hot cores, with temperatures around 200 K, and relative abundances 0.2-2 × 10 −8 for CH 3 CN and 0.6-5 × 10 −6 for CH 3 OH. The two cores with highest mass (cores A and B) show coherent velocity fields, with gradients almost aligned with the dust elongated structure. Those velocity gradients are consistent with Keplerian disks rotating about central masses of 4-18 M . Perpendicular to the velocity gradients we have identified a large-scale precessing jet/outflow associated with core B, and hints of an east-west jet/outflow associated with core A. Conclusions. The elongated dust structure in G35.20−0.74 N is fragmented into a number of dense cores that may form high-mass stars. Based on the velocity field of the dense gas, the orientation of the magnetic field, and the regularly spaced fragmentation, we interpret this elongated structure as the densest part of a 1D filament fragmenting and forming high-mass stars.

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“…Davis et al (2010) strictly defined molecular hydrogen emissionline objects (MHOs) as the near-infrared manifestations of outflows, and presented a comprehensive catalog of around 1000 MHOs. Deep, wide-field near-infrared imaging with the combination of narrow-band H 2 filter and the corresponding A&A 553, A41 (2013) filter for continuum emission such as a Ks filter has become a very efficient method to detect and identify MHOs (Stanke et al 2002;Khanzadyan et al 2004;Davis et al 2008;Froebrich et al 2011). Morphology, proper motion, as well as association with an HH object or CO outflow, can all provide information concerning the location of the driving source.…”

Section: Introductionmentioning

confidence: 99%

Proper motions of molecular hydrogen outflows in theρOphiuchi molecular cloud

Zhang

Brandner

Wang

et al. 2013

A&A

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Context. Proper motion measurements provide unique and powerful means to identify the driving sources of mass outflows, which are of particular importance in regions with complex star formation activity and deeply embedded protostars. They also provide the necessary kinematic information to study the dynamics of mass outflows, the interaction between outflows and the ambient medium, and the evolution of outflows with the age of the driving sources. Aims. We aim to take a census of molecular hydrogen emission line objects (MHOs) in the ρ Ophiuchi molecular cloud and to make the first systematic proper motion measurements of these objects in this region. The driving sources are identified based on the measured proper motions, and the outflow properties are characterized. The relationship between outflow properties and the evolutionary stages of the driving sources are also investigated. Methods. Deep H 2 near-infrared imaging is performed to search for molecular hydrogen emission line objects. Multi-epoch data are used to derive the proper motions of the features of these objects, and the lengths and opening angles of the molecular hydrogen outflows. Results. Our imaging covers an area of ∼0.11 deg 2 toward the L1688 core in the ρ Ophiuchi molecular cloud. In total, six new MHOs are discovered, 32 previously known MHOs are detected, and the proper motions for 86 features of the MHOs are measured. The proper motions lie in the range of 14 to 247 mas/yr, corresponding to transversal velocities of 8 to 140 km s −1 with a median velocity of about 35 km s −1 . Based on morphology and proper motion measurements, 27 MHOs are ascribed to 21 driving sources. The molecular hydrogen outflows have a median length of ∼0.04 pc and random orientations. We find no obvious correlation between H 2 jet length, jet opening angle, and the evolutionary stage of the driving sources as defined by their spectral indices. We find that the fraction of protostars (23%) that drive molecular hydrogen outflows is similar to the one for Class II sources (15%). For most molecular hydrogen outflows, no obvious velocity variation along the outflow has been found. Conclusions. In Ophiuchus the frequency of occurrence of molecular hydrogen outflows has no strong dependency on the evolutionary stage of the driving source during the evolution from the protostellar stage to the classical T Tauri stage.

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UWISH2 - the UKIRT Widefield Infrared Survey for H2

Cited by 72 publications

References 92 publications

YSO jets in the Galactic plane from UWISH2 – III. Jets and outflows in Cassiopeia and Auriga

YSO jets in the Galactic plane from UWISH2 – III. Jets and outflows in Cassiopeia and Auriga

A necklace of dense cores in the high-mass star forming region G35.20−0.74 N: ALMA observations

Proper motions of molecular hydrogen outflows in theρOphiuchi molecular cloud

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