We analyze stellar streams in action-angle coordinates combined with recent
local direct acceleration measurements to provide joint constraints on the
potential of our Galaxy. Our stream analysis uses the Kullback-Leibler
divergence with a likelihood analysis based on the two-point correlation
function. We provide joint constraints from pulsar accelerations and stellar
streams for local and global parameters that describe the potential of the
Milky Way (MW). Our goal is to build an ``acceleration ladder", where direct
acceleration measurements that are currently limited in dynamic range are
combined with indirect techniques that can access a much larger volume of the
MW. To constrain the MW potential with stellar streams, we consider the Palomar
5, Orphan, Nyx, Helmi and GD1 streams. Of the potential models that we have
considered here, the preferred potential for the streams is a two-component
Staeckel potential. We also compare the vertical accelerations from stellar
streams and pulsar timing, defining a function $f(z)={\alpha}_{1pulsar}z-\frac{\partial \mathrm{\Phi}}{\partial z}$ , where $\mathrm{\Phi}$ is the MW potential determined
from stellar streams, and ${\alpha}_{1\text{}\mathrm{p}\mathrm{u}\mathrm{l}\mathrm{s}\mathrm{a}\mathrm{r}}z$ is the vertical acceleration
determined from pulsar timing observations. Our analysis indicates that the
Oort limit determined from streams is consistently (regardless of the choice of
potential) lower than that determined from pulsar timing observations. The
calibration we have derived here may be used to correct the estimate of the
acceleration from stellar streams.

PREPRINT

# Building an Acceleration Ladder with Tidal Streams and Pulsar Timing

Peter Craig, Sukanya Chakrabarti, Robyn E. Sanderson, Farnik Nikakhtar

Submitted on 1 November 2022

## Abstract

## Preprint

Comment: 8 pages, 4 figures, 1 table. Submitted to ApJ Letters

Subject: Astrophysics - Astrophysics of Galaxies