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- Leal-Ferreira, M. L., et al.
(författare)
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Rotten Egg nebula: the magnetic field of a binary evolved star
- 2012
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Ingår i: Astronomy and Astrophysics. - : EDP Sciences. - 0004-6361 .- 1432-0746. ; 540, s. Article Number: A42-
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Tidskriftsartikel (refereegranskat)abstract
- Context. Most of the planetary nebulae (PNe) observed are not spherical. The loss of spherical symmetry occurs somewhere between the asymptotic giant branch (AGB) phase and the PNe phase. The cause of this change of morphology is not yet well understood, but magnetic fields are one of the possible agents. The origin of the magnetic field remains to be determined, and potentially requires the presence of a massive companion to the AGB star. Therefore, further detections of the magnetic field around evolved stars, and in particular those thought to be part of a binary system, are crucial to improve our understanding of the origin and role of magnetism during the late stages of stellar evolution. One such binary is the pre-PN OH231.8+4.2, around which a magnetic field has previously been detected in the OH maser region of the outer circumstellar envelope. Aims. We aim to detect and infer the properties of the magnetic field of the pre-PN OH231.8+4.2 in the H2O maser region that probes the region close to the central star. This source is a confirmed binary with collimated outflows and an envelope containing several maser species. Methods. In this work we observed the 6(1,6)-5(2,3) H2O maser rotational transition to determine its linear and circular polarization. As a result of Zeeman splitting, the properties of the magnetic field can be derived from maser polarization analysis. The H2O maser emissions of OH231.8+4.2 are located within the inner regions of the source (at a few tens of AU). Results. We detected 30 H2O maser features around OH231.8+4.2. The masers occur in two distinct regions that are moving apart with a velocity on the sky of 2.3 mas/year. Taking into account the inclination angle of the source with the line of sight, this corresponds to an average separation velocity of 21 km s(-1). Based on the velocity gradient of the maser emission, the masers appear to be dragged along the direction of the nebula jet. Linear polarization is present in three of the features, and circular polarization is detected in the two brightest features. The circular polarization results imply a magnetic field strength of vertical bar B-parallel to vertical bar similar to 45 mG. Conclusions. We confirm the presence of a magnetic field around OH231.8+4.2, and report the first measurements of its strength within a few tens of AU of the stellar pair. Assuming a toroidal magnetic field, this imples B similar to 2.5 G on the stellar surface. The morphology of the field is not yet determined, but the high scatter found in the directions of the linear polarization vectors could indicate that the masers occur near the tangent points of a toroidal field.
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| 2. |
- Leal-Ferreira, M.L., et al.
(författare)
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Water Maser Emission Around Low/Intermediate Mass Evolved Stars
- 2012
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Ingår i: Proceedings of the International Astronomical Union. - 1743-9213 .- 1743-9221. ; 8:S287, s. 79 - 80
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- We present results of Very Long Baseline Array (VLBA) polarimetric 22 GHz H2O maser observations of a number of low/intermediate mass evolved stars. We observed 3 Miras (Ap Lyn, IK Tau and IRC+60370), 1 semi-regular variable (RT Vir) and 1 pPN (OH231.8+4.2). Circular polarization is detected in the H2O maser region of OH231.8+4.2 and we infer a magnetic field of |B||| = ~45 mG. This implies an extrapolated magnetic field of ~2.5 G on the surface of the central star. The preliminary results on RT Vir and IRC+60370 also indicate the first detection of weak H2O maser linear polarization.
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| 3. |
- Shaw, D. J., et al.
(författare)
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Expect the Unexpected? Variations in Question Type Elicit Cues to Deception in Joint Interviewer Contexts
- 2013
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Ingår i: Applied Cognitive Psychology. - : Wiley. - 0888-4080 .- 1099-0720. ; 27:3, s. 336-343
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Tidskriftsartikel (refereegranskat)abstract
- We examined the effect of (i) a second interviewer's demeanour and (ii) asking expected and unexpected questions on cues to deception. We predicted that liars compared with truth tellers would provide more detail to expected questions and less detail to unexpected questions, particularly when the second interviewer is supportive. Liars prepare answers for expected questions, and a supportive interviewer will encourage them to provide more detail. By definition, liars have not prepared answers for unexpected questions, and their answers to such questions will be less detailed. Participants (N=168) appeared before two interviewers: The first asked all the questions, and the second remained silent. The second interviewer exhibited either a supportive or a neutral demeanour. As predicted, liars provided more detail to expected questions and less detail to unexpected questions, particularly when the second interviewer was supportive. In conclusion, a supportive second interviewer elicits cues to deceit. Copyright (c) 2013 John Wiley & Sons, Ltd.
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| 4. |
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| 5. |
- Mann, S, et al.
(författare)
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Two heads are better than one? How to effectively use two interviewers to elicit cues to deception
- 2013
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Ingår i: Legal and Criminological Psychology. - 1355-3259. ; 18:2, s. 324-340
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Tidskriftsartikel (refereegranskat)abstract
- Background. We examined the effect of a second interviewer’s demeanour on cues to deception. We predicted that a supportive demeanour would be the most beneficial for eliciting verbal cues to deceit, as it would encourage truth tellers, but not liars, to say more. In addition, we examined the extent to which interviewees deliberately made eye contact with the interviewers. Liars take their credibility less for granted than truth tellers, and therefore have a greater drive to be convincing. Liars are thus more likely to monitor the interviewer to determine if the interviewer appears to believe them. Method. Participants appeared before two interviewers: the first asked all the questions and the second remained silent. The second interviewer exhibited either a supportive, neutral, or a suspicious demeanour. Results. Truth tellers provided significantly more detail than liars, but only in the supportive second interviewer condition. The effect of a second interviewer’s demeanour on detail was perhaps remarkable given that the interviewees hardly looked at the second interviewer (less than 10% of the time). Liars displayed more deliberate eye contact (with the first interviewer) than truth tellers did. Conclusions. A supportive second interviewer has a positive effect on interviewing. We discuss this finding in the wider contexts of investigative interviewing and interviewing to detect deception.
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| 8. |
- Ramstedt, Sofia, et al.
(författare)
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The wonderful complexity of the Mira AB system
- 2014
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Ingår i: Astronomy and Astrophysics. - : EDP Sciences. - 0004-6361 .- 1432-0746. ; 570, s. Art. no. L14-
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Tidskriftsartikel (refereegranskat)abstract
- We have mapped the (CO)-C-12(3-2) line emission around the Mira AB system at 0 ''.5 resolution using the Atacama Large Millimeter/submillimeter Array (ALMA). The CO map shows amazing complexity. The circumstellar gas has been shaped by different dynamical actors during the evolution of the system, and several morphological components can be identified. The companion is marginally resolved in continuum emission and is currently at 0 ''.487 +/- 0 ''.006 separation. In the main line component, centered on the stellar velocity, spiral arcs around Mira A are found. The spiral appears to be relatively flat and oriented in the orbital plane. An accretion wake behind the companion is clearly visible, and the projected arc separation is about 5 ''. In the blue wing of the line emission, offset from the main line, several large (similar to 5-10 '') opposing arcs are found. We tentatively suggest that this structure is created by the wind of Mira B blowing a bubble in the expanding envelope of Mira A.
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| 9. |
- Shaw, D, et al.
(författare)
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‘We'll Take It from Here’: The Effect of Changing Interviewers in Information Gathering Interviews
- 2014
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Ingår i: Applied Cognitive Psychology. - : Wiley. - 0888-4080 .- 1099-0720. ; 28:6, s. 908-916
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Tidskriftsartikel (refereegranskat)abstract
- Summary: A common strategy in interviewing is to repeatedly focus on the same topics, for example by asking to recall an event first in chronological order and then in reverse order. We examined the effect of changing interviewers between the two questions or keeping the same interviewers throughout on cues to deception. Truth tellers may be most encouraged to recall again what they have witnessed when confronted with new interviewers, as these new interviewers have not heard their story before. Liars may be most encouraged to recall again their story when confronted with the same interviewers, realising that these interviewers will check for consistency in their answers. The impact of changing interviewers should lead to more pronounced differences between truth tellers and liars in terms of detail and repetition in the ‘Changed Interviewers’ condition compared with the ‘Same Interviewers’ condition. Participants were interviewed by two interviewers about a mock security meeting they attended. In half the interviews, the same two interviewers remained throughout, and in the other half, two new interviewers took over half-way through. As predicted, differences between truth tellers and liars in terms of detail and repetition were most pronounced in the ‘Changed Interviewers’ condition. Changing interviewers during an interview effectively differentiates liars and truth tellers with respect to detail and repetition. We discuss this finding and its place within investigative interviewing and deception detection literature.
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| 10. |
- Vrij, A, et al.
(författare)
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Collective interviewing of suspects
- 2012
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Ingår i: Journal of Applied Research in Memory and Cognition. - 2211-3681. ; 1:4, s. 41-44
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Tidskriftsartikel (refereegranskat)abstract
- When people are interviewed about possible wrongdoing that has been committed in groups, they typically are interviewed separately. Yet, in several settings it would be more intuitive and convenient to interview suspects together. Importantly, such collective interviews could yield verbal cues to deception. This is the first deception experiment to investigate collective interviewing. Twenty-one pairs of truth tellers and 22 pairs of liars were interviewed pair-wise about having had lunch together in a restaurant. Given that truth tellers adopt a “tell it all” strategy in the interviews while, in contrast, liars prefer to keep their stories simple, we predicted that pairs of truth tellers would (i) interrupt and (ii) correct each other more, and would (iii) add more information to each other’s answers than pairs of liars. The results supported these hypotheses. Theory-driven interventions to elicit more cues to deception through simultaneous interviewing are discussed.
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