skysurvey-skyfield

Skysurvey extension containing 3D density-velocity fields for accurate 3D-sky distribution

Installation

using pip:

pip install skysurvey-skyfield

Concept

skysurvey-skyfield top level functions are expected to returns RA, Dec, zcosmo, vpec etc. that can be then be used in a skysurvey target model.

import skysurvey
import skysurvey_skyfield

model_3d = {"radecz": {"func": func_returning___ra_dec_z_vpec,
                      #"kwargs": {}, # function's options
                       "as":["ra", "dec", "z", "vpec"] # stroring names
			}
          }
snia = skysurvey.SNIa.from_draw(5_000, model=model_3d)

Example

Draw RA, Dec, zcosmo and vpec, and then get "z" the observed redshift.

import skysurvey
import skysurvey_skyfield
import numpy as np

def get_random_3d(size, rate, 
                  zmin=0, zmax=1, zstep=1e-4, # redshift
                  skyarea=None, ra_range=[0, 360], dec_range=[-90, 90], # radec
                  vpec_prop = {"loc": 0, "scale":300},
                  **kwargs
                 ):
    """ randomly drawing ra, dec, zcosmo and vpec independently """
    from skysurvey.tools.utils import random_radec
    from skysurvey.target import rates
    
    # random draw in the sky
    ra, dec = random_radec(size=size, skyarea=skyarea,
				ra_range=ra_range, dec_range=dec_range)

    # redshift follow the rate
    zcosmo = rates.draw_redshift(size, rate, zmin=zmin, zmax=zmax, zstep=zstep,
				skyarea=skyarea, **kwargs)

    # random vpec
    vpec = np.random.normal(size=size, **vpec_prop)
    return ra, dec, zcosmo, vpec

def zcosmo_to_zobs(zcosmo, vpec):
    """ transform zcosmo into observed redshift given peculiar velocity """
    from astropy.constants import c
    return (1 + zcosmo) * (1+vpec/c.to("km/s").value) - 1

    
# build the model
model_3d = {"radecz": {"func": get_random_3d,
                      #"kwargs": {}, # function's options
                       "as":["ra", "dec", "zcosmo", "vpec"] # stroring names
			},
            "z": {"func": zcosmo_to_zobs,
                 "kwargs": {"zcosmo":"@zcosmo", "vpec":"@vpec"},
                 }
          }

snia = skysurvey.SNeIa.from_draw(5_000, model=model_3d, zmax=0.1)
snia.data.head(5)

	x1	c	t0	ra	dec	zcosmo	vpec	magabs	z	magobs	x0	template
0	-0.235	0.093	56144.2	85.6558	-17.7259	0.07105	-376.761	-19.1435	0.069704	18.4155	0.000683036	salt2
1	0.6	0.141	56038	107.037	-16.8615	0.08895	-710.863	-19.0464	0.0863679	19.0028	0.000397679	salt2
2	0.37	0.064	56148.8	219.088	51.774	0.07595	284.344	-19.062	0.0769705	18.7232	0.000514477	salt2
3	0.4	0.081	56049.1	278.101	-47.1459	0.08795	205.612	-19.175	0.0886962	18.9354	0.000423146	salt2
4	-0.57	0.049	56071.4	186.988	28.0833	0.08375	341.405	-19.0145	0.0849842	18.9976	0.000399589	salt2

MickaelRigault/skysurvey-skyfield

skysurvey-skyfield

Installation

Concept

Example