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102 Chapter 3. LS 5039 as a runaway microquasar field). The arrow in this figure marks the proper motion sense of LS 5039 as it would be seen from the LSR (i.e., correction for the peculiar velocity of the Sun has been applied), while the dashed line represents the trajectory in the past up to 10 5 yr, with the corresponding error boxes in position at that epoch and 5 × 10 4 yr ago. From this figure we can see that LS 5039 crosses the projection in the plane of the sky of SNR G016.8−01.1 between ∼ 4 × 10 4 and ∼ 1.3 × 10 5 years ago. If one of the two stars forming a close binary system experiences a SN explosion, it may form a SNR and an X-ray binary. Since conservation of the linear momentum after the SN explosion is required, if the SNR and the X-ray binary are related, we expect them to be aligned with the proper motion of the latter, and any deviation from this behavior should be explained by the projection in the plane of the sky of the initial space velocity of the binary system prior to the SN event. This does not seem to be the case here, because SNR G016.8−01.1 and LS 5039 are not well aligned with the LS 5039 proper motion. Moreover, if we assume that the center of the shell- like remnant is located at the minimum of radio emission in Fig. 3.2, approximately located at α = 18 h 25 m 03 s , δ = −14 ◦ 37 ′ 30 ′′ (or l = 16.94 ◦ , b = −0.93 ◦ ), a peculiar velocity in the plane of the sky for the original system of 70 km s −1 is obtained. This velocity is much higher than the typical ∼ 10 km s −1 found for early-type stars. In order to reduce this velocity we can use in our favor the error in the proper motion angle, and find that it turns out to be 50 km s −1 , which is still too high. However, the center of the shell-like remnant could be in another position, closer to the LS 5039 trajectory, and the derived peculiar velocity for the system prior to the SN explosion could fit in the typical values of early-type stars. Hence, from the kinematical point of view, we are not able to firmly discard a possible association between both objects. Therefore, we have performed an in-depth study of the remnant. SNR G016.8−01.1 was discovered by Reich et al. (1986) using a combination of survey data analysis and new multifrequency observations. The extended radio source has a complex structure due to the superposition of the H ii-region RCW 164 (Rodgers et al. 1960), which is coincident with the peak of the continuum emission (in black in Fig. 3.2). The diffuse radiation observed around the peak is strongly polarized (Rodgers et al. 1960), indicating a synchrotron nature. Polarization de- creases towards the position of the foreground H ii-region as a result of the thermal contribution. Thermal and non-thermal components of the radiation cannot be clearly separated, but the total flux from the SNR at 5 GHz seems to be ∼ 1 Jy
3.4. SNR G016.8−01.1 103 Normalized Intensity 1,4 1,2 1,0 0,8 0,6 0,4 0,2 0,0 -0,2 -0,4 -0,6 -100 -80 -60 -40 -20 0 20 40 60 80 Velocity (km/s) Figure 3.3: H166α line observations of the H ii-region RCW 164. The solid line represents a Gaussian fit to the data, with its maximum being at v = 16.5 ± 0.8 km s −1 . (J. A. Combi, private communication). The angular diameter of the remnant is ∼ 30 ′ , and its distance remains unknown. 3.4.1 A lower limit of the distance In order to determine a lower limit of the distance to SNR G016.8−01.1, we car- ried out H166α recombination line (1424.734 MHz) observations of the foreground H ii-region on 2000 November 17. We used a 30-m radiotelescope at the Instituto Argentino de Radioastronomía (IAR), Villa Elisa. The receiver is a helium-cooled HEMT amplifier with a 1008-channel autocorrelator at the back end. The HPBW at a wavelength of 21 cm is 30 ′ and the temperature of the system on the cold sky during the observations was about 35 K. The H166α line was detected at a velocity of 16.5 ± 0.8 km s −1 (see Fig. 3.3) after 1.5 hours of integration time, with a signal-to-noise ratio of ∼ 4. At a location of l ≈ 16.8 ◦ , b ≈ −1.1 ◦ , standard galactic rotation models (Fich et al. 1989) indicate that the observed velocity corresponds to a distance d ∼ 1.8 kpc. Consequently, SNR G016.8−01.1 should be farther than ∼ 2 kpc, as suggested by its relatively small angular size.
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UNIVERSITAT DE BARCELONA Departamen
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Per a la meva neboda Blanca, que va
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feina no presentada en aquesta tesi
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desfogar-nos conjuntament, per la s
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From the scientifical point of view
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Gràcies a la meva germana Nàdia,
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ii CONTENTS I Discovery and study o
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iv CONTENTS II A search for new mic
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vi CONTENTS
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viii Resum de la tesi d’Eddington
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x Resum de la tesi imprescindible p
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xii Resum de la tesi dels sistemes
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xiv Resum de la tesi un comportamen
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xvi Resum de la tesi MilliARC SEC 4
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xviii Resum de la tesi per poder de
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xx Resum de la tesi valors força s
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xxii Resum de la tesi 2. D’entre
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xxiv Resum de la tesi pano Alemán
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xxvi Resum de la tesi 3.3 Observaci
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xxviii Resum de la tesi habitual en
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xxx Resum de la tesi Per tant, si l
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xxxii BIBLIOGRAFIA
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2 Chapter 1. Introduction and backg
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10 Chapter 1. Introduction and back
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28 BIBLIOGRAPHY Lewin, W. H. G., va
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30 BIBLIOGRAPHY
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Chapter 2 Multiwavelength approach
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2.3. An interesting target in the s
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2.4. The radio counterpart: NVSS J1
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Page 111 and 112: 2.6. The X-ray counterpart: RX J182
Page 121 and 122: 2.7. The γ-ray counterpart: 3EG J1
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Page 127 and 128: Figure 2.23: Scenario where the mul
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Page 135 and 136: Bibliography Blandford, R. D., & K
Page 137 and 138: BIBLIOGRAPHY 91 Merck, M., Bertsch,
Page 139 and 140: Chapter 3 LS 5039 as a runaway micr
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Page 145 and 146: 3.3. The past trajectory of LS 5039
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Page 157 and 158: 3.6. Discussion 111 At this point w
Page 159 and 160: 3.7. Conclusions 113 6. Finally, th
Page 161 and 162: Bibliography Ankay, A., Kaper, L.,
Page 163 and 164: BIBLIOGRAPHY 117 Schaerer, D., de K
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Page 168 and 169: 122 Chapter 4. The cross-identifica
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Page 180 and 181: DECLINATION (J2000) DECLINATION (J2
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152 Chapter 6. EVN and MERLIN obser
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166 BIBLIOGRAPHY
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General conclusions 171 Since each
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