¹ Departamento de Astronomia, Instituto de Astronomia ...
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Extended H 2 Emission Towards a Sample of Massive YSOs Felipe Navarete¹ ([email protected]), Augusto Damineli¹, Cássio L. Barbosa 2 , Robert D. Blum 3 ¹ Departamento de Astronomia, Instituto de Astronomia, Geofísica e Ciências Atmosféricas, Universidade de São Paulo, São Paulo, Brasil. ² UNIVAP,São José dos Campos, SP, Brasil. 3 NOAO Gemini Science Center, Tucson, Arizona, USA. Observations e Methodology References Lumsden S. L., Hoare M. G., Oudmaijer R. D., Richards D., 2002, MNRAS, 366, 621 Mottram J. C., Hoare M. G., Urquhart J. S., et al., 2011, A&A, 525, A149 Urquhart J. S., Busfield A. L., Hoare M. G., et al., 2007, A&A, 474, 891 Urquhart J. S., Busfield A. L., Hoare M. G., et al., 2008, A&A, 487, 253 Varricatt W. P., Davis C. J., Ramsay S., Todd S. P., et al., 2010, MNRAS, 404, 661 Massive Star Formation Main Conclusions -150 sources (50%) display extended H 2 emission and 62 of them are polar; -The low fraction of sources associated with polar jets (≈ 21%) indicates a short timescale of such structures. -Diffuse H 2 emission is mostly found towards stellar clusters. -The analysis of the aspect ratio of the structures indicates that higher luminosity sources produce less collimated outflows. -Follow up observations using Gemini/NIFS (Navarete et al., in prep.) or ALMA/VLA maps would reveal (or not) the massive nature of the best targets. Fig 2. Spartan/SOAR observations of the Southern sample. The images were observed with Spartan over 2011A-2012B. Left: RGB image of the field (Continuum in red, Continuum+H 2 in green and H 2 in blue). Right: Continuum-subtracted H 2 map. Excess in H 2 is shown in blue and excess in the continuum is shown in red. The circle at the center of the field corresponds to the position of the MSX source and has a diameter of 18”. Results: Polar Emission and Comparison with Other Works Fig 1. WIRCam/CFHT observations of the Northern sample. The images were observed with WIRCam over 2010B-2012A. Left: RGB image of the field (Continuum in red, Continuum+H 2 in green and H 2 in blue). Right: Continuum-subtracted H 2 map. Excess in H 2 is shown in blue and excess in the continuum is shown in red. The circle at the center of the field corresponds to the position of the MSX source and has a diameter of 18”. 4 classes of H 2 morphology: BPn: polar emission, with n poles (BP1: monopolar; BP2: bipolar; BP5: multipolar) K: knot or flocular H 2 emission D: diffuse H 2 emission N: non-detected extended H 2 emission Each source was classified according to its NIR properties: 1) NIR counterpart 2) Extended continuuum emission (due to free-free emission or dust scattering) 3) Association with Stellar cluster Observations: Narrow-band H 2 images (2.12 μm) and continuum (2.14 μm). 1) Spartan+OSIRIS / SOAR (Chile): 183 Southern targets 2) WIRCam / CFHT (Hawaii): 113 Northern targets Data Processing - THELI: final images with astrometric errors < 0.1” for both CFHT and SOAR data. Follow-up Observations: NIR IFU/Radio observations to determine the dynamical masses of the best MYSO candidates. H 2 Morphology and NIR properties E) F) D) B) C) A) Fig 4. Bipolar sources and comparison with Varricatt et al. (2010). The sources of the present work are shown in green while those from V10 are shown in red. The number of sources correspond to the peak of each distribution is shown in the corresponding color at its top. A) Distribution of the bolometric luminosity. B) Distribution of the projected dimension of the polar emissions. The black arrows correspond to the limits observed by Wu et al. (2006). C) Distribution of the aspect ratio of the polar emissions. D and E: The projected dimension and aspect ratio of each outflow as a function of the luminosity of the central source. Results: General Properties of the Sample Fig 3. Classification of the sample. The number of sources are shown at the top of each bar. Negative results are shown in red. A) Detection of Extended H 2 emission towards the sample. B) Morphology of the H 2 emission toward each MSX source. C) Classification of the BP sources. D, E and F: NIR Counterpart of the MSX sources (D) detection of extended continuum emission (E) and association with stellar clusters (Panel F) as a function of the H 2 morphology. Very few massive stars in early formation stages were clearly identified in our Galaxy. The formation process of these objects are still unclear and two theories predict the formation of massive stars: i) by merging of low mass stars or ii) by an accretion disk. There are no critical observational evidences to choose between them. The lack of observational evidences combined to the low number of known massive stars in formation in our Galaxy does not allow us to choose between these scenarios. We present a near-infrared survey of MYSOs candidates selected from the Red MSX Source survey. Such catalog is based on an accurate revision of distances and luminosities, overcoming the failures in previous searches of this kind. 376 targets were observed through the H 2 narrow-band filter at 2.12 μm and in the continuum to identify collimated molecular jets. 296 of these targets were successfully processed using the THELI pipeline. This work Varricatt (2010)
Transcript of ¹ Departamento de Astronomia, Instituto de Astronomia ...
Extended H2 Emission Towards a Sample of Massive YSOsFelipe Navarete¹ ([email protected]), Augusto Damineli¹, Cássio L. Barbosa2, Robert D. Blum3
¹ Departamento de Astronomia, Instituto de Astronomia, Geofísica e Ciências Atmosféricas, Universidade de São Paulo, São Paulo, Brasil.² UNIVAP,São José dos Campos, SP, Brasil. 3 NOAO Gemini Science Center, Tucson, Arizona, USA.
Observations e Methodology
ReferencesLumsden S. L., Hoare M. G., Oudmaijer R. D., Richards D., 2002, MNRAS, 366, 621Mottram J. C., Hoare M. G., Urquhart J. S., et al., 2011, A&A, 525, A149Urquhart J. S., Busfield A. L., Hoare M. G., et al., 2007, A&A, 474, 891Urquhart J. S., Busfield A. L., Hoare M. G., et al., 2008, A&A, 487, 253Varricatt W. P., Davis C. J., Ramsay S., Todd S. P., et al., 2010, MNRAS, 404, 661
Massive Star Formation
Main Conclusions
-150 sources (50%) display extended H2 emission and 62 of them are polar;
-The low fraction of sources associated with polar jets (≈ 21%) indicates ashort timescale of such structures.
-Diffuse H2 emission is mostly found towards stellar clusters.
-The analysis of the aspect ratio of the structures indicates that higherluminosity sources produce less collimated outflows.
-Follow up observations using Gemini/NIFS (Navarete et al., in prep.) orALMA/VLA maps would reveal (or not) the massive nature of the besttargets.
Fig 2. Spartan/SOAR observations of the Southern sample. The images were observed with Spartan over 2011A-2012B. Left:RGB image of the field (Continuum in red, Continuum+H2 in green and H2 in blue). Right: Continuum-subtracted H2 map. Excess inH2 is shown in blue and excess in the continuum is shown in red. The circle at the center of the field corresponds to the position ofthe MSX source and has a diameter of 18”.
Results: Polar Emission and Comparison with Other WorksFig 1. WIRCam/CFHT observations of the Northern sample. The images were observed with WIRCam over 2010B-2012A.Left: RGB image of the field (Continuum in red, Continuum+H2 in green and H2 in blue). Right: Continuum-subtracted H2 map.Excess in H2 is shown in blue and excess in the continuum is shown in red. The circle at the center of the field corresponds to theposition of the MSX source and has a diameter of 18”.
4 classes of H2 morphology:BPn: polar emission, with n poles(BP1: monopolar; BP2: bipolar; BP5: multipolar)
K: knot or flocular H2 emissionD: diffuse H2 emissionN: non-detected extended H2 emission
Each source was classified according to itsNIR properties:1) NIR counterpart2) Extended continuuum emission
(due to free-free emission or dust scattering)
3) Association with Stellar cluster
Observations: Narrow-band H2 images(2.12 μm) and continuum (2.14 μm).
1) Spartan+OSIRIS / SOAR (Chile):183 Southern targets
2) WIRCam / CFHT (Hawaii):113 Northern targets
Data Processing - THELI: final imageswith astrometric errors < 0.1” for bothCFHT and SOAR data.
Follow-up Observations: NIR IFU/Radioobservations to determine the dynamicalmasses of the best MYSO candidates.
H2 Morphology and NIR properties
E) F)D)
B) C)A)
Fig 4. Bipolar sources and comparison with Varricatt et al. (2010). The sources of the present work are shown in green whilethose from V10 are shown in red. The number of sources correspond to the peak of each distribution is shown in the correspondingcolor at its top. A) Distribution of the bolometric luminosity. B) Distribution of the projected dimension of the polar emissions. Theblack arrows correspond to the limits observed by Wu et al. (2006). C) Distribution of the aspect ratio of the polar emissions.D and E: The projected dimension and aspect ratio of each outflow as a function of the luminosity of the central source.
Results: General Properties of the Sample
Fig 3. Classification of the sample. The number of sources are shown at the top of each bar. Negative results are shown in red.A) Detection of Extended H2 emission towards the sample. B) Morphology of the H2 emission toward each MSX source.C) Classification of the BP sources. D, E and F: NIR Counterpart of the MSX sources (D) detection of extended continuum emission(E) and association with stellar clusters (Panel F) as a function of the H2 morphology.
Very few massive stars in early formation stages were clearly identified in ourGalaxy. The formation process of these objects are still unclear and two theories predictthe formation of massive stars: i) by merging of low mass stars or ii) by an accretiondisk. There are no critical observational evidences to choose between them. The lack ofobservational evidences combined to the low number of known massive stars information in our Galaxy does not allow us to choose between these scenarios.
We present a near-infrared survey of MYSOs candidates selected from the RedMSX Source survey. Such catalog is based on an accurate revision of distances andluminosities, overcoming the failures in previous searches of this kind. 376 targets wereobserved through the H2 narrow-band filter at 2.12 μm and in the continuum to identifycollimated molecular jets. 296 of these targets were successfully processed using theTHELI pipeline.
This work
Varricatt (2010)
