We report the detection of the H 2 v =1-0 S(1) line at 2.122 µm, from RNO 91 in the L43 dark clou... more We report the detection of the H 2 v =1-0 S(1) line at 2.122 µm, from RNO 91 in the L43 dark cloud, which is known to be a T Tauri star surrounded by a 1700AU disk structure (containing ices) and a weak outflow. The non-detection of the H 2 v =2-1 S(1) line at 2.247 µm suggests shock excitation rather than fluorescence. The emission is extended spatially up to 9 in the north-south direction. The line intensity peak (FWHM ∼ 3 ) corresponds to the star RNO 91 which is embedded in a cocoon of gas and dust. The observed H 2 emission from this cocoon may be attributed to embedded Herbig-Haro like knots. The H 2 line flux in the central 2 × 3 is estimated to be 7 × 10 −14 ergs sec −1 cm −2 , which indicates a mass flow rate of 4 × 10 −8 M yr −1 . Furthermore, narrow band image taken through H 2 1-0 S(1) filter is presented, which reveal a tilted disk and bipolar outflow structure that agrees with earlier observations and models. We show that this disk/outflow system is a unique case.
... during the observations with CGS 4. We also sincerely thank Reinhard Mundt, Melvin Hoare, Joc... more ... during the observations with CGS 4. We also sincerely thank Reinhard Mundt, Melvin Hoare, Jochen Eislöffel, Mark McCaughrean and Hans Zinnecker for many instructive and enjoyable hours spent discussing jets and outflows, and Alex Raga for his comments as referee. ...
Proceedings of the International Astronomical Union
Submillimetre CO mapping of the outflows in HH25/26 Abstract Andy G. Gibb Electronic Engineering ... more Submillimetre CO mapping of the outflows in HH25/26 Abstract Andy G. Gibb Electronic Engineering Laboratory, University of Kent at Canterbury ... REFERENCES Bontemps S., André P., Ward-Thompson D., 1995, A&A, 297, 98 Bontemps S., André P., Terebey S., Cabrit S., 1996 ...
We report the detection of the H 2 v =1-0 S(1) line at 2.122 µm, from RNO 91 in the L43 dark clou... more We report the detection of the H 2 v =1-0 S(1) line at 2.122 µm, from RNO 91 in the L43 dark cloud, which is known t ob eaTT auri star surrounded by a 1700AU disk structure (containing ices) and a weak outflow. The non-detection of the H 2 v =2-1 S(1) line at 2.247 µm suggests shock excitation rather than fluorescence. The emission is extended spatially up to 9 in the north-south direction. The line intensity peak (FWHM ∼ 3 ) corresponds to the star RNO 91 which is embedded in a cocoon of gas and dust. The observed H 2 emission from this cocoon may be attributed to embedded Herbig-Haro like knots. The H 2 line flux in the central 2 × 3 is estimated to be 7 × 10 −14 ergs sec −1 cm −2 , which indicates a mass flow rate of 4 × 10 −8 M yr −1 . Furthermore, narrow band image taken through H 2 1-0 S(1) filter is presented, which reveal a tilted disk and bipolar outflow structure that agrees with earlier observations and models. We show that this disk/outflow system is a unique case.
We present new medium-resolution longslit spectra in the near-infrared and examine the excitation... more We present new medium-resolution longslit spectra in the near-infrared and examine the excitation of molecular hydrogen across several outflows from young stars. In contrast to previous studies, in which the brightest patches in the flows were selected, we find evidence for variations in excitation with position within several sources.
We report here on the first proper-motion measurements of molecular hydrogen emission features in... more We report here on the first proper-motion measurements of molecular hydrogen emission features in the Herbig-Haro 46/47 outflow. Assuming a distance of 350 pc to this flow, the inferred tangential velocities range from a few tens to almost 500 km s Ϫ1 . The highest velocities are observed for H 2 knots either in, or close to, the jet/ counterjet axes. Knots constituting the wings of the large-scale H 2 bow are found to move much more slowly. These results appear to be in agreement with recent numerical simulations of H 2 emission from pulsed jets. We also report the first detection of variability in H 2 features for a young stellar object (YSO) outflow. It was found that several H 2 knots significantly changed their luminosity over the 4 yr time base used to conduct our study. This is in line with current estimates for the cooling time of gas radiating shocked H 2 emission in YSO environments.
Optical, near-infrared, and sub-millimetre observations of the outflow from the young (Class I/Cl... more Optical, near-infrared, and sub-millimetre observations of the outflow from the young (Class I/Class 0) source RNO 15-FIR indicate that it is jet-driven, and that the "prompt" or bow shock entrainment mechanism dominates over "turbulent" entrainment. The CO J=3-2 observations presented in this paper reveal a collimated, bipolar, molecular outflow driven by RNO 15-FIR. The peaks in the CO outflow lobes are coincident with compact H 2 line emission features. We also find that the mass and momentum distributions in both flow lobes decrease with distance from the source, and that localised "peaks" in these distributions coincide with the H 2 knots. It is likely, therefore, that the H 2 knots represent bow shocks along the jet which accelerate ambient gas into the flow via a prompt entrainment mechanism.
This study investigated the linguistic processing of visual speech (video of a talker&amp... more This study investigated the linguistic processing of visual speech (video of a talker's utterance without audio) by determining if such has the capacity to prime subsequently presented word and nonword targets. The priming procedure is well suited for the investigation of whether speech perception is amodal since visual speech primes can be used with targets presented in different modalities. To this end, a series of priming experiments were conducted using several tasks. It was found that visually spoken words (for which overt identification was poor) acted as reliable primes for repeated target words in the naming, written and auditory lexical decision tasks. These visual speech primes did not produce associative or reliable form priming. The lack of form priming suggests that the repetition priming effect was constrained by lexical level processes. That priming found in all tasks is consistent with the view that similar processes operate in both visual and auditory speech processing.
Journal of Experimental Child Psychology, Jul 1, 2007
A masked priming procedure was used to explore developmental changes in the tuning of lexical wor... more A masked priming procedure was used to explore developmental changes in the tuning of lexical word recognition processes. Lexical tuning was assessed by examining the degree of masked form priming and used two different types of prime-target lexical similarity: one letter different (e.g., rlay fi PLAY) and transposed letters (e.g., lpay fi PLAY). The performance of skilled adult readers was compared with that of developing readers in Grade 3. The same children were then tested again two years later, when they were in Grade 5. The skilled adult readers showed no form priming, indicating that their recognition mechanisms for these items had become finely tuned. In contrast, the Grade 3 readers showed substantial form priming effects for both measures of lexical similarity. When retested in Grade 5, the developing readers no longer showed significant one letter different priming, but transposed letter priming remained. In general, these results provide evidence for a transition from more broadly tuned to more finely tuned lexical recognition mechanisms and are interpreted in the context of models of word recognition.
We report the detection of the H 2 v =1-0 S(1) line at 2.122 µm, from RNO 91 in the L43 dark clou... more We report the detection of the H 2 v =1-0 S(1) line at 2.122 µm, from RNO 91 in the L43 dark cloud, which is known to be a T Tauri star surrounded by a 1700AU disk structure (containing ices) and a weak outflow. The non-detection of the H 2 v =2-1 S(1) line at 2.247 µm suggests shock excitation rather than fluorescence. The emission is extended spatially up to 9 in the north-south direction. The line intensity peak (FWHM ∼ 3 ) corresponds to the star RNO 91 which is embedded in a cocoon of gas and dust. The observed H 2 emission from this cocoon may be attributed to embedded Herbig-Haro like knots. The H 2 line flux in the central 2 × 3 is estimated to be 7 × 10 −14 ergs sec −1 cm −2 , which indicates a mass flow rate of 4 × 10 −8 M yr −1 . Furthermore, narrow band image taken through H 2 1-0 S(1) filter is presented, which reveal a tilted disk and bipolar outflow structure that agrees with earlier observations and models. We show that this disk/outflow system is a unique case.
... during the observations with CGS 4. We also sincerely thank Reinhard Mundt, Melvin Hoare, Joc... more ... during the observations with CGS 4. We also sincerely thank Reinhard Mundt, Melvin Hoare, Jochen Eislöffel, Mark McCaughrean and Hans Zinnecker for many instructive and enjoyable hours spent discussing jets and outflows, and Alex Raga for his comments as referee. ...
Proceedings of the International Astronomical Union
Submillimetre CO mapping of the outflows in HH25/26 Abstract Andy G. Gibb Electronic Engineering ... more Submillimetre CO mapping of the outflows in HH25/26 Abstract Andy G. Gibb Electronic Engineering Laboratory, University of Kent at Canterbury ... REFERENCES Bontemps S., André P., Ward-Thompson D., 1995, A&A, 297, 98 Bontemps S., André P., Terebey S., Cabrit S., 1996 ...
We report the detection of the H 2 v =1-0 S(1) line at 2.122 µm, from RNO 91 in the L43 dark clou... more We report the detection of the H 2 v =1-0 S(1) line at 2.122 µm, from RNO 91 in the L43 dark cloud, which is known t ob eaTT auri star surrounded by a 1700AU disk structure (containing ices) and a weak outflow. The non-detection of the H 2 v =2-1 S(1) line at 2.247 µm suggests shock excitation rather than fluorescence. The emission is extended spatially up to 9 in the north-south direction. The line intensity peak (FWHM ∼ 3 ) corresponds to the star RNO 91 which is embedded in a cocoon of gas and dust. The observed H 2 emission from this cocoon may be attributed to embedded Herbig-Haro like knots. The H 2 line flux in the central 2 × 3 is estimated to be 7 × 10 −14 ergs sec −1 cm −2 , which indicates a mass flow rate of 4 × 10 −8 M yr −1 . Furthermore, narrow band image taken through H 2 1-0 S(1) filter is presented, which reveal a tilted disk and bipolar outflow structure that agrees with earlier observations and models. We show that this disk/outflow system is a unique case.
We present new medium-resolution longslit spectra in the near-infrared and examine the excitation... more We present new medium-resolution longslit spectra in the near-infrared and examine the excitation of molecular hydrogen across several outflows from young stars. In contrast to previous studies, in which the brightest patches in the flows were selected, we find evidence for variations in excitation with position within several sources.
We report here on the first proper-motion measurements of molecular hydrogen emission features in... more We report here on the first proper-motion measurements of molecular hydrogen emission features in the Herbig-Haro 46/47 outflow. Assuming a distance of 350 pc to this flow, the inferred tangential velocities range from a few tens to almost 500 km s Ϫ1 . The highest velocities are observed for H 2 knots either in, or close to, the jet/ counterjet axes. Knots constituting the wings of the large-scale H 2 bow are found to move much more slowly. These results appear to be in agreement with recent numerical simulations of H 2 emission from pulsed jets. We also report the first detection of variability in H 2 features for a young stellar object (YSO) outflow. It was found that several H 2 knots significantly changed their luminosity over the 4 yr time base used to conduct our study. This is in line with current estimates for the cooling time of gas radiating shocked H 2 emission in YSO environments.
Optical, near-infrared, and sub-millimetre observations of the outflow from the young (Class I/Cl... more Optical, near-infrared, and sub-millimetre observations of the outflow from the young (Class I/Class 0) source RNO 15-FIR indicate that it is jet-driven, and that the "prompt" or bow shock entrainment mechanism dominates over "turbulent" entrainment. The CO J=3-2 observations presented in this paper reveal a collimated, bipolar, molecular outflow driven by RNO 15-FIR. The peaks in the CO outflow lobes are coincident with compact H 2 line emission features. We also find that the mass and momentum distributions in both flow lobes decrease with distance from the source, and that localised "peaks" in these distributions coincide with the H 2 knots. It is likely, therefore, that the H 2 knots represent bow shocks along the jet which accelerate ambient gas into the flow via a prompt entrainment mechanism.
This study investigated the linguistic processing of visual speech (video of a talker&amp... more This study investigated the linguistic processing of visual speech (video of a talker's utterance without audio) by determining if such has the capacity to prime subsequently presented word and nonword targets. The priming procedure is well suited for the investigation of whether speech perception is amodal since visual speech primes can be used with targets presented in different modalities. To this end, a series of priming experiments were conducted using several tasks. It was found that visually spoken words (for which overt identification was poor) acted as reliable primes for repeated target words in the naming, written and auditory lexical decision tasks. These visual speech primes did not produce associative or reliable form priming. The lack of form priming suggests that the repetition priming effect was constrained by lexical level processes. That priming found in all tasks is consistent with the view that similar processes operate in both visual and auditory speech processing.
Journal of Experimental Child Psychology, Jul 1, 2007
A masked priming procedure was used to explore developmental changes in the tuning of lexical wor... more A masked priming procedure was used to explore developmental changes in the tuning of lexical word recognition processes. Lexical tuning was assessed by examining the degree of masked form priming and used two different types of prime-target lexical similarity: one letter different (e.g., rlay fi PLAY) and transposed letters (e.g., lpay fi PLAY). The performance of skilled adult readers was compared with that of developing readers in Grade 3. The same children were then tested again two years later, when they were in Grade 5. The skilled adult readers showed no form priming, indicating that their recognition mechanisms for these items had become finely tuned. In contrast, the Grade 3 readers showed substantial form priming effects for both measures of lexical similarity. When retested in Grade 5, the developing readers no longer showed significant one letter different priming, but transposed letter priming remained. In general, these results provide evidence for a transition from more broadly tuned to more finely tuned lexical recognition mechanisms and are interpreted in the context of models of word recognition.
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