Anomaly detection in the Zwicky Transient Facility DR3

The feature data set extracted from ZTF DR3 light curves. It was used in Malanchev et al. 2020 to detect anomalous astrophysical sources in ZTF data. 

"feature_XXX.dat" files contain object-ordered light curve feature data, every object is built on 42 feature values, which are encoded as little endian single precision IEEE-754 float (32bit float) numbers. Feature code-names are the same for all three data sets and are listed in plain text files "feature_XXX.name", one code-name per line. "oid_XXX.dat" files contain ZTF DR object identifiers encoded as little endian 64-bit unsigned integer numbers. "oid_XXX.dat" and "feature_XXX.dat" have same object order, for example the first 8 bytes of "oid_m31.dat" files contain the OID of the ZTF DR3 light curve which feature are presented in the first 168 bytes of "feature_m31.dat" file. "m31", "deep" and "disk" denote different ZTF fields and contain 57 546, 406 611, 1 790 565 objects. Note that observations between 58194 ≤ MJD ≤ 58483 are used, see the paper for field and features details.

The sample Python code to access the data as Numpy arrays:

import numpy as np

oid = np.memmap('oid_m31.dat', mode='r', dtype=np.uint64)
with open('feature_m31.name') as f:
names = f.read().split()
dtype = [(name, np.float32) for name in names]
feature = np.memmap('feature_m31.dat', mode='r', dtype=dtype, shape=oid.shape)

idx = np.argmax(feature['amplitude'])
print('Object {} has maximum amplitude {:.3f}'.format(oid[idx], feature['amplitude'][idx]))