Interaction of the supernova remnant G18.8+0.3 with the surrounding medium

We have carried out a study of the interaction of the supernova remnant (SNR) G18.8+0.3 with the surrounding interstellar medium. Observations of the H I, 12CO, 13CO, and OH (1720 MHz) lines were performed toward a large field around G18.8+0.3 using the Parkes (Australia) 64 m single-dish telescope,...

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Autores principales:	Dubner, G., Giacani, E., Reynoso, E., Goss, W.M., Roth, M., Green, A.
Formato:	JOUR
Materias:	Ism: clouds ISM: H I Ism: individual (G18.8+0.3 = Kesteven 67) Ism: molecules Supernova remnants
Acceso en línea:	http://hdl.handle.net/20.500.12110/paper_00046256_v118_n2_p930_Dubner
Aporte de:	Biblioteca Digital - Facultad de Ciencias Exactas y Naturales (UBA) de Universidad de Buenos Aires

id	todo:paper_00046256_v118_n2_p930_Dubner
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spelling	todo:paper_00046256_v118_n2_p930_Dubner2023-10-03T13:59:37Z Interaction of the supernova remnant G18.8+0.3 with the surrounding medium Dubner, G. Giacani, E. Reynoso, E. Goss, W.M. Roth, M. Green, A. Ism: clouds ISM: H I Ism: individual (G18.8+0.3 = Kesteven 67) Ism: molecules Supernova remnants We have carried out a study of the interaction of the supernova remnant (SNR) G18.8+0.3 with the surrounding interstellar medium. Observations of the H I, 12CO, 13CO, and OH (1720 MHz) lines were performed toward a large field around G18.8+0.3 using the Parkes (Australia) 64 m single-dish telescope, the 4 m NANTEN millimetric telescope (Las Campanas Observatory, Chile), and the Very Large Array (NRAO). The present survey has revealed the existence of an elongated molecular cloud (about 21′ × 6′ in size) adjacent to the more flattened borders of the SNR and to the far side of the remnant. The overall CO and H I morphology and kinematics allow us to conclude that the explosion occurred near the border of a preexisting molecular cloud, driving a slow shock into the cloud. The presence of diffuse shock-heated dust with a color temperature of about 30 K was shown in coincidence with the molecular feature using IRAS data. The shocked CO and H I gas was detected between +10 and +27 km s-1 (LSR). The systemic velocity of this complex, about +19 km s-1, yields a kinematic distance of about 1.9 kpc for G18.8+0.3. The shock is presently expanding into the cloud at ∼10 km s-1. Masses of the order of 7300, 1100, and 55 M⊙ are estimated for the associated molecular hydrogen, atomic hydrogen, and heated dust, respectively. The total kinetic energy transferred by the supernova shock to the surrounding interstellar medium is of the order of 1049 ergs. An age of ∼16,000 yr is calculated for G18.8+0.3. The extended molecular feature with a density of ∼600 cm-3 has denser clumps immersed in it, with densities ranging from ∼2500 to ∼6000 cm-3. Three out of five of these clumps were found to contain luminous IRAS pointlike sources compatible with protostellar candidates, suggesting a causal relationship with the supernova explosion that deserves further investigation. The interferometric search for OH (1720 MHz) masers gave negative results. These OH masers can be short-lived occurrences and dissipate quickly in the cooling postshock gas because of the very restrictive conditions under which masers form. Therefore, their absence does not preclude the hypothesis of shock-cloud interaction. JOUR info:eu-repo/semantics/openAccess http://creativecommons.org/licenses/by/2.5/ar http://hdl.handle.net/20.500.12110/paper_00046256_v118_n2_p930_Dubner
institution	Universidad de Buenos Aires
institution_str	I-28
repository_str	R-134
collection	Biblioteca Digital - Facultad de Ciencias Exactas y Naturales (UBA)
topic	Ism: clouds ISM: H I Ism: individual (G18.8+0.3 = Kesteven 67) Ism: molecules Supernova remnants
spellingShingle	Ism: clouds ISM: H I Ism: individual (G18.8+0.3 = Kesteven 67) Ism: molecules Supernova remnants Dubner, G. Giacani, E. Reynoso, E. Goss, W.M. Roth, M. Green, A. Interaction of the supernova remnant G18.8+0.3 with the surrounding medium
topic_facet	Ism: clouds ISM: H I Ism: individual (G18.8+0.3 = Kesteven 67) Ism: molecules Supernova remnants
description	We have carried out a study of the interaction of the supernova remnant (SNR) G18.8+0.3 with the surrounding interstellar medium. Observations of the H I, 12CO, 13CO, and OH (1720 MHz) lines were performed toward a large field around G18.8+0.3 using the Parkes (Australia) 64 m single-dish telescope, the 4 m NANTEN millimetric telescope (Las Campanas Observatory, Chile), and the Very Large Array (NRAO). The present survey has revealed the existence of an elongated molecular cloud (about 21′ × 6′ in size) adjacent to the more flattened borders of the SNR and to the far side of the remnant. The overall CO and H I morphology and kinematics allow us to conclude that the explosion occurred near the border of a preexisting molecular cloud, driving a slow shock into the cloud. The presence of diffuse shock-heated dust with a color temperature of about 30 K was shown in coincidence with the molecular feature using IRAS data. The shocked CO and H I gas was detected between +10 and +27 km s-1 (LSR). The systemic velocity of this complex, about +19 km s-1, yields a kinematic distance of about 1.9 kpc for G18.8+0.3. The shock is presently expanding into the cloud at ∼10 km s-1. Masses of the order of 7300, 1100, and 55 M⊙ are estimated for the associated molecular hydrogen, atomic hydrogen, and heated dust, respectively. The total kinetic energy transferred by the supernova shock to the surrounding interstellar medium is of the order of 1049 ergs. An age of ∼16,000 yr is calculated for G18.8+0.3. The extended molecular feature with a density of ∼600 cm-3 has denser clumps immersed in it, with densities ranging from ∼2500 to ∼6000 cm-3. Three out of five of these clumps were found to contain luminous IRAS pointlike sources compatible with protostellar candidates, suggesting a causal relationship with the supernova explosion that deserves further investigation. The interferometric search for OH (1720 MHz) masers gave negative results. These OH masers can be short-lived occurrences and dissipate quickly in the cooling postshock gas because of the very restrictive conditions under which masers form. Therefore, their absence does not preclude the hypothesis of shock-cloud interaction.
format	JOUR
author	Dubner, G. Giacani, E. Reynoso, E. Goss, W.M. Roth, M. Green, A.
author_facet	Dubner, G. Giacani, E. Reynoso, E. Goss, W.M. Roth, M. Green, A.
author_sort	Dubner, G.
title	Interaction of the supernova remnant G18.8+0.3 with the surrounding medium
title_short	Interaction of the supernova remnant G18.8+0.3 with the surrounding medium
title_full	Interaction of the supernova remnant G18.8+0.3 with the surrounding medium
title_fullStr	Interaction of the supernova remnant G18.8+0.3 with the surrounding medium
title_full_unstemmed	Interaction of the supernova remnant G18.8+0.3 with the surrounding medium
title_sort	interaction of the supernova remnant g18.8+0.3 with the surrounding medium
url	http://hdl.handle.net/20.500.12110/paper_00046256_v118_n2_p930_Dubner
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_version_	1807316890202144768

Interaction of the supernova remnant G18.8+0.3 with the surrounding medium

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