...
首页> 外文期刊>The Astrophysical journal >PRECISION ASTROMETRY WITH THE VERY LONG BASELINE ARRAY: PARALLAXES AND PROPER MOTIONS FOR 14 PULSARS
【24h】

PRECISION ASTROMETRY WITH THE VERY LONG BASELINE ARRAY: PARALLAXES AND PROPER MOTIONS FOR 14 PULSARS

机译:极长基线阵列的精密天文测量:14个脉冲的视差和正确运动

获取原文

摘要

Astrometry can bring powerful constraints to bear on a variety of scientific questions about neutron stars, including their origins, astrophysics, evolution, and environments. Using phase-referenced observations at the Very Long Baseline Array (VLBA), in conjunction with pulsar gating and in-beam calibration, we have measured the parallaxes and proper motions for 14 pulsars. The smallest measured parallax in our sample is 0.13 ± 0.02 mas for PSR B1541+09, which has a most probable distance of 7.2+1.3 –1.1 kpc. We detail our methods, including initial VLA surveys to select candidates and find in-beam calibrators, VLBA phase-referencing, pulsar gating, calibration, and data reduction. The use of the bootstrap method to estimate astrometric uncertainties in the presence of unmodeled systematic errors is also described. Based on our new model-independent estimates for distance and transverse velocity, we investigate the kinematics and birth sites of the pulsars and revisit models of the Galactic electron density distribution. We find that young pulsars are moving away from the Galactic plane, as expected, and that age estimates from kinematics and pulsar spindown are generally in agreement, with certain notable exceptions. Given its present trajectory, the pulsar B2045 – 16 was plausibly born in the open cluster NGC 6604. For several high-latitude pulsars, the NE2001 electron density model underestimates the parallax distances by a factor of 2, while in others the estimates agree with or are larger than the parallax distances, suggesting that the interstellar medium is irregular on relevant length scales. The VLBA astrometric results for the recycled pulsar J1713+0747 are consistent with two independent estimates from pulse timing, enabling a consistency check between the different reference frames.
机译:占星术可以带来强大的约束,以约束有关中子星的各种科学问题,包括它们的起源,天体物理学,演化和环境。使用超长基线阵列(VLBA)的相位参考观测值,结合脉冲星选通和光束内校准,我们测量了14个脉冲星的视差和适当运动。对于我们的样品,PSR B1541 + 09的最小实测视差为0.13±0.02 mas,其最可能的距离为7.2 + 1.3 –1.1 kpc。我们将详细介绍我们的方法,包括进行初始VLA调查以选择候选物并找到光束中的校准器,VLBA相位参考,脉冲星选通,校准和数据缩减。还介绍了使用Bootstrap方法估算未建模系统误差时的天文不确定性。基于我们对距离和横向速度的新模型独立估计,我们研究了脉冲星的运动学和出生地点,并重新考察了银河电子密度分布模型。我们发现,如预期的那样,年轻的脉冲星正在远离银河平面,并且从运动学和脉冲星降落运动得出的年龄估计总体上是一致的,但有一些明显的例外。根据其当前的轨迹,脉冲星B2045 – 16可能是在疏散星团NGC 6604中诞生的。对于几个高纬度脉冲星,NE2001电子密度模型将视差距离低估了2倍,而在另一些情况下,估计则与或一致。大于视差距离,表明星际介质在相关的长度尺度上是不规则的。回收脉冲星J1713 + 0747的VLBA天文测量结果与脉冲定时的两个独立估计值一致,从而可以检查不同参考系之间的一致性。

著录项

获取原文

客服邮箱:kefu@zhangqiaokeyan.com

京公网安备:11010802029741号 ICP备案号:京ICP备15016152号-6 六维联合信息科技 (北京) 有限公司©版权所有
  • 客服微信

  • 服务号