ztflc

LightCurve Estimation from ZTF data

Credit

M. Rigault (corresponding author, m.rigault@ipnl.in2p3.fr, CNRS/IN2P3). A similar code exists here, used for the ZTF high cadence SNeIa paper Yao et al. 2019.

ztflc is however solely based on ztfquery.

Acknowledgment

If you have used ztflc for a research you are publishing, please include the following in your acknowledgments: "The ztflc code was funded by the European Research Council (ERC) under the European Union's Horizon 2020 research and innovation programme (grant agreement n°759194 - USNAC, PI: Rigault)."

Usage

First time using ztflc

1. You may want to make sure $ZTFDATA is defined (see ztfquery.)
2. You should first run Storing or updating marshal data. for your marshal's science program.

Example 1, force photometry from coordinates:

For a target with coordinates ra, dec, you want to do force photometry on ZTF data from julian data jdmin up to julian date jdmax:

from ztflc import forcephotometry
# Setup the target
fp = forcephotometry.ForcePhotometry.from_coords(ra, dec, jdmin=jdmin,jdmax=jdmax)
# Load the ztf metadata
fp.load_metadata()
# Load the ztf file you are going to need (diffimg and psfimg)
fp.load_filepathes()
# and run the forcephotometry
fp.run_forcefit(verbose=True)

Once the force photometry has run, data are stored as:

fp.data_forcefit

and use fp.show_lc() to plot the lightcurve.

To store the date_forcefit, simply do:

fp.store()

the dataframe will be store in $ZTFDATA/forcephotometry/name.csv (c.f. ztfquery for $ZTFDATA). you can also directly provide the filename if you want to dataframe stored elsewhere fp.store(filename).

Example 2, from ztf target name:

Say you want to get the force photometry from a ztf target named ZTF18aaaaaaa. Use the same code as example 1, except that, this time, you load fp using:

from ztflc import forcephotometry
# Setup the target
fp = forcephotometry.ForcePhotometry.from_name(ZTF18aaaaaaa)

the code will use ztfquery.marshal to recover the information you need (ra, dec jdmin, jdmax).

Storing or updating marshal data.

You can store ztf mashal target information locally using ztfquery. For instance, if you want to store the "Cosmology" program, simply do:

from ztfquery import marshal
m = marshal.MarshalAccess()
m.load_target_sources("Cosmology")
m.store()

Once you did that, the code will use the locally stored data when you use forcephotometry.ForcePhotometry.from_name(ZTF18aaaaaaa)

Downloading the files you need.

The first time you are going to run the forcephotometry for a given target, you most likely need to download the associated data. For instance for ZTF18aaaaaaa

from ztflc import forcephotometry
# Setup the target
fp = forcephotometry.ForcePhotometry.from_name(ZTF18aaaaaaa)
# Download the data:
fp.io.download_data()