Proper Motion of the Neutron Star in the Supernova Remnant G18.9–1.1

In this paper, we present the first direct measurement of the proper motion of the neutron star (NS) in the supernova remnant (SNR) G18.9−1.1 using a 15 yr Chandra baseline. After correcting the observations’ astrometric solutions using reference Gaia stars’ positions, we measure a total proper moti...

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Main Authors: Tyler Holland-Ashford, Brian Williams, Patrick Slane, Xi Long
Format: Article
Language:English
Published: IOP Publishing 2025-01-01
Series:The Astrophysical Journal
Subjects:
Online Access:https://doi.org/10.3847/1538-4357/adeb7e
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author Tyler Holland-Ashford
Brian Williams
Patrick Slane
Xi Long
author_facet Tyler Holland-Ashford
Brian Williams
Patrick Slane
Xi Long
author_sort Tyler Holland-Ashford
collection DOAJ
description In this paper, we present the first direct measurement of the proper motion of the neutron star (NS) in the supernova remnant (SNR) G18.9−1.1 using a 15 yr Chandra baseline. After correcting the observations’ astrometric solutions using reference Gaia stars’ positions, we measure a total proper motion of 24.7 ± 6.8 mas yr ^−1 at an angle of 336° ± 16° east of north. Using the distance estimates from the literature of 2.1 and 3.8 kpc, this proper motion corresponds to Galactic rotation-corrected transverse velocities of 264d _2.1 ± 79 km s ^−1 and 474d _3.8 ± 129 km s ^−1 , respectively. Our power ratio method analysis of SNR ejecta slightly favors the higher velocity, as multipole moments calculated from the back-evolved center using the farther distance are more consistent with values from other CCSNRs. The NS’s motion is directly opposite the motion of bulk ejecta in G18.9−1.1, providing yet more evidence that NS kicks are generated via a conservation of momentum-like process between the NS and the ejecta, as has been observed in other SNRs.
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spelling doaj-art-42457db44d484200b710a319228f22a92025-08-20T03:36:12ZengIOP PublishingThe Astrophysical Journal1538-43572025-01-01988221810.3847/1538-4357/adeb7eProper Motion of the Neutron Star in the Supernova Remnant G18.9–1.1Tyler Holland-Ashford0https://orcid.org/0000-0002-7643-0504Brian Williams1https://orcid.org/0000-0003-2063-381XPatrick Slane2https://orcid.org/0000-0002-6986-6756Xi Long3https://orcid.org/0000-0003-3350-1832Astrophysics Science Division , NASA Goddard Space Flight Center Greenbelt, MD 20771, USA ; tyler.e.holland-ashford@nasa.govAstrophysics Science Division , NASA Goddard Space Flight Center Greenbelt, MD 20771, USA ; tyler.e.holland-ashford@nasa.govCenter for Astrophysics ∣ Harvard & Smithsonian , 60 Garden Street, Cambridge, MA 02138, USADepartment of Physics, The University of Hong Kong , Pokfulam Road, Hong KongIn this paper, we present the first direct measurement of the proper motion of the neutron star (NS) in the supernova remnant (SNR) G18.9−1.1 using a 15 yr Chandra baseline. After correcting the observations’ astrometric solutions using reference Gaia stars’ positions, we measure a total proper motion of 24.7 ± 6.8 mas yr ^−1 at an angle of 336° ± 16° east of north. Using the distance estimates from the literature of 2.1 and 3.8 kpc, this proper motion corresponds to Galactic rotation-corrected transverse velocities of 264d _2.1 ± 79 km s ^−1 and 474d _3.8 ± 129 km s ^−1 , respectively. Our power ratio method analysis of SNR ejecta slightly favors the higher velocity, as multipole moments calculated from the back-evolved center using the farther distance are more consistent with values from other CCSNRs. The NS’s motion is directly opposite the motion of bulk ejecta in G18.9−1.1, providing yet more evidence that NS kicks are generated via a conservation of momentum-like process between the NS and the ejecta, as has been observed in other SNRs.https://doi.org/10.3847/1538-4357/adeb7eNeutron starsCore-collapse supernovaeX-ray point sourcesSupernova remnantsStellar kinematics
spellingShingle Tyler Holland-Ashford
Brian Williams
Patrick Slane
Xi Long
Proper Motion of the Neutron Star in the Supernova Remnant G18.9–1.1
The Astrophysical Journal
Neutron stars
Core-collapse supernovae
X-ray point sources
Supernova remnants
Stellar kinematics
title Proper Motion of the Neutron Star in the Supernova Remnant G18.9–1.1
title_full Proper Motion of the Neutron Star in the Supernova Remnant G18.9–1.1
title_fullStr Proper Motion of the Neutron Star in the Supernova Remnant G18.9–1.1
title_full_unstemmed Proper Motion of the Neutron Star in the Supernova Remnant G18.9–1.1
title_short Proper Motion of the Neutron Star in the Supernova Remnant G18.9–1.1
title_sort proper motion of the neutron star in the supernova remnant g18 9 1 1
topic Neutron stars
Core-collapse supernovae
X-ray point sources
Supernova remnants
Stellar kinematics
url https://doi.org/10.3847/1538-4357/adeb7e
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