If we want to get the message in one line of sight , such as the velocity of LOS or the distance of LOS , how can we do to confirm one line of sight and get useful data ?
Dylan Nelson
5 Apr '21
Hello,
I'm afraid I don't understand exactly what you are trying to do, can you explain more?
If you want to determine a physical property of gas, stars, or dark matter along a particular sight-line in a simulation snapshot, you can load the particle data, and then search for particles which are near to (or intersect) the sightline.
Yan Shulan
5 Apr '21
Thanks, Dylan.
Actually, I want to get some physical properties along a particular sight-line. But before loading the particle data, I need load the subhalos data first. And I don't know how many particles in the subhalo intersect the sightline. Or briefly, how can I get the full particle data which may be in different subhalos in one direction. What's more, I also want to know how to calculate the velocity of line of sight. In your API data access, using {vis_query} can get the png image of vel_los, if I need the data of vel_los, how can I get it ?
Dylan Nelson
5 Apr '21
Hello,
(1) There isn't any fast or easy way to know which particles, or which subhalos, intersect a sightline. You must load their Coordinates (or e.g. SubhaloPos) and check.
(2) The most simple approach is to take a LOS which is along one of the x,y,z axes of the simulation box. So if the LOS direction is z, then the LOS velocity is exactly the Velocities[2] field. If the LOS direction is x, then it is Velocities[0].
If we want to get the message in one line of sight , such as the velocity of LOS or the distance of LOS , how can we do to confirm one line of sight and get useful data ?
Hello,
I'm afraid I don't understand exactly what you are trying to do, can you explain more?
If you want to determine a physical property of gas, stars, or dark matter along a particular sight-line in a simulation snapshot, you can load the particle data, and then search for particles which are near to (or intersect) the sightline.
Thanks, Dylan.
Actually, I want to get some physical properties along a particular sight-line. But before loading the particle data, I need load the subhalos data first. And I don't know how many particles in the subhalo intersect the sightline. Or briefly, how can I get the full particle data which may be in different subhalos in one direction. What's more, I also want to know how to calculate the velocity of line of sight. In your API data access, using {vis_query} can get the png image of vel_los, if I need the data of vel_los, how can I get it ?
Hello,
(1) There isn't any fast or easy way to know which particles, or which subhalos, intersect a sightline. You must load their
Coordinates(or e.g.SubhaloPos) and check.(2) The most simple approach is to take a LOS which is along one of the
x,y,zaxes of the simulation box. So if the LOS direction isz, then the LOS velocity is exactly theVelocities[2]field. If the LOS direction isx, then it isVelocities[0].Thank you very much