Measuring proper motions of isolated neutron stars with Chandra

2007 ◽  
pp. 217-224
Author(s):  
Christian Motch ◽  
Adriana M. Pires ◽  
Frank Haberl ◽  
Axel Schwope
Keyword(s):  
Neutron Stars ◽  
Proper Motions

scholarly journals Measuring proper motions of isolated neutron stars with Chandra

2007 ◽  
Vol 308 (1-4) ◽  
pp. 217-224 ◽  
Author(s):  
Christian Motch ◽  
Adriana M. Pires ◽  
Frank Haberl ◽  
Axel Schwope
Keyword(s):  
Neutron Stars ◽  
Proper Motions

scholarly journals The Determination of the Proper Motions of X-Ray Sources

1970 ◽  
Vol 7 ◽  
pp. 164-166
Author(s):  
Heinrich Eichhorn ◽  
George D. Gatewood ◽  
Sabatino Sofia
Keyword(s):  
Neutron Star ◽  
Neutron Stars ◽  
Proper Motion ◽  
South Florida ◽  
The Other ◽  
Proper Motions ◽  
X Ray ◽  
Other Information ◽  
The University

At the University of South Florida Observatory, a program is under way to determine the proper motions of the star-like objects which are possibly or probably associated with X-Ray sources. The objects under study are Sco X-l, and objects believed to be identical with Cen X-2, Cyg X-2, and Co D -32° 1057. Since it has been speculated that these might be neutron stars, an effort was made to study not only their proper motions but also those of other stars in the neighborhood to ascertain membership of any moving cluster with known age and distance, whereby their own ages and distances might become known. These efforts were successful so far in the case of ScoX-1 (Sofia, Eichhorn and Gatewood, 1969), whose proper motion is virtually identical to that which a member of theScorpio-Centaurus Association would have at this position, so that the membership of Sco X-l in this association becomes highly probable. On the basis of this and other information, Gatewood and Sofia (1969) conclude that Sco X-l is quite likely a neutron star. The reduction was described in detail by Gatewood (1968). No definitive results are available yet for the other three objects.

The art of precision pulsar timing

2009 ◽  
Vol 5 (S261) ◽  
pp. 212-217 ◽  
Author(s):  
Matthew Bailes
Keyword(s):  
Magnetic Field ◽  
General Relativity ◽  
Neutron Stars ◽  
Internal Structure ◽  
Millisecond Pulsar ◽  
Proper Motions ◽  
Tests Of General Relativity ◽  
Timing Precision ◽  
Pulsar Timing ◽  
Field Strengths

AbstractPulsar timing has proven to be a wonderful tool with which to study neutron stars, providing insights into their ages, distances, proper motions, magnetic field strengths, internal structure, binary histories and evolution, and for tests of General Relativity. Here I describe how to optimise strategies for millisecond pulsar timing to enable the highest timing precision.

scholarly journals Constraining the masses of microlensing black holes and the mass gap with Gaia DR2

2020 ◽  
Vol 636 ◽  
pp. A20 ◽  
Author(s):  
Łukasz Wyrzykowski ◽  
Ilya Mandel
Keyword(s):  
Black Holes ◽  
Black Hole ◽  
Neutron Stars ◽  
Continuous Distribution ◽  
Compact Object ◽  
Proper Motions ◽  
Mass Gap ◽  
Wide Range ◽  
The Masses ◽  
Black Hole Masses

Context. Gravitational microlensing is sensitive to compact-object lenses in the Milky Way, including white dwarfs, neutron stars, or black holes, and could potentially probe a wide range of stellar-remnant masses. However, the mass of the lens can be determined only in very limited cases, due to missing information on both source and lens distances and their proper motions. Aims. Our aim is to improve the mass estimates in the annual parallax microlensing events found in the eight years of OGLE-III observations towards the Galactic Bulge with the use of Gaia Data Release 2 (DR2). Methods. We use Gaia DR2 data on distances and proper motions of non-blended sources and recompute the masses of lenses in parallax events. We also identify new events in that sample which are likely to have dark lenses; the total number of such events is now 18. Results. The derived distribution of masses of dark lenses is consistent with a continuous distribution of stellar-remnant masses. A mass gap between neutron star and black hole masses in the range between 2 and 5 solar masses is not favoured by our data, unless black holes receive natal kicks above 20−80 km s−1. We present eight candidates for objects with masses within the putative mass gap, including a spectacular multi-peak parallax event with mass of 2.4−1.3+1.9 M⊙ located just at 600 pc. The absence of an observational mass gap between neutron stars and black holes, or conversely the evidence of black hole natal kicks if a mass gap is assumed, can inform future supernova modelling efforts.

scholarly journals Proper motions of thermally emitting isolated neutron stars measured with Chandra

2009 ◽  
Vol 497 (2) ◽  
pp. 423-435 ◽  
Author(s):  
C. Motch ◽  
A. M. Pires ◽  
F. Haberl ◽  
A. Schwope ◽  
V. E. Zavlin
Keyword(s):  
Neutron Stars ◽  
Proper Motions

Galactic orbits of stars

1966 ◽  
Vol 25 ◽  
pp. 93-97
Author(s):  
Richard Woolley
Keyword(s):  
Globular Cluster ◽  
Potential Field ◽  
High Velocity ◽  
Velocity Vector ◽  
Variable Stars ◽  
The Sun ◽  
Proper Motions ◽  
Rr Lyrae ◽  
The Galaxy

It is now possible to determine proper motions of high-velocity objects in such a way as to obtain with some accuracy the velocity vector relevant to the Sun. If a potential field of the Galaxy is assumed, one can compute an actual orbit. A determination of the velocity of the globular clusterωCentauri has recently been completed at Greenwich, and it is found that the orbit is strongly retrograde in the Galaxy. Similar calculations may be made, though with less certainty, in the case of RR Lyrae variable stars.

The Lick Program of Absolute Proper Motions

1962 ◽  
Vol 11 (02) ◽  
pp. 404-405
Author(s):  
S. Vasilevskis
Keyword(s):  
Proper Motions

Catalogue reduction techniques

1978 ◽  
Vol 48 ◽  
pp. 389-390 ◽  
Author(s):  
Chr. de Vegt
Keyword(s):  
Adjustment Process ◽  
Proper Motions ◽  
Measuring Process ◽  
Aerial Photogrammetry ◽  
Reduction Techniques ◽  
Observational Technique ◽  
The Common ◽  
Astrometric Data

AbstractReduction techniques as applied to astrometric data material tend to split up traditionally into at least two different classes according to the observational technique used, namely transit circle observations and photographic observations. Although it is not realized fully in practice at present, the application of a blockadjustment technique for all kind of catalogue reductions is suggested. The term blockadjustment shall denote in this context the common adjustment of the principal unknowns which are the positions, proper motions and certain reduction parameters modelling the systematic properties of the observational process. Especially for old epoch catalogue data we frequently meet the situation that no independent detailed information on the telescope properties and other instrumental parameters, describing for example the measuring process, is available from special calibration observations or measurements; therefore the adjustment process should be highly self-calibrating, that means: all necessary information has to be extracted from the catalogue data themselves. Successful applications of this concept have been made already in the field of aerial photogrammetry.

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