Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Evidence for photometric activity cycles in 3203 Kepler stars   In recent years it has been claimed that the length of stellar activity
cycles is determined by the stellar rotation rate. It is observed that the
cycle period increases with rotation period along the so-called active and
inactive sequences. In this picture the Sun occupies a solitary position in
between the two sequences. Our goal is to measure cyclic variations of the
stellar light curve amplitude and the rotation period using four years of
Kepler data. Periodic changes of the light curve amplitude or the stellar
rotation period are associated with an underlying activity cycle. Using the
McQuillan et al. 2014 sample we compute the rotation period and the variability
amplitude for each Kepler quarter and search for periodic variations of both
time series. To test for periodicity in each stellar time series we consider
Lomb-Scargle periodograms and use a selection based on a False Alarm
Probability (FAP). We detect amplitude periodicities in 3203 stars between
0.5-6 years covering rotation periods between 1-40 days. Given our sample size
of 23,601 stars and our selection criteria that the FAP is less than 5%, this
number is almost three times higher than that expected from pure noise. We do
not detect periodicities in the rotation period beyond those expected from
noise. Our measurements reveal that the cycle period shows a weak dependence on
rotation rate, slightly increasing for longer rotation period. We further show
that the shape of the variability deviates from a pure sine curve, consistent
with observations of the solar cycle. Our measurements do not support the
existence of distinct sequences in the P_rot-P_cyc plane, although there is
some evidence for the inactive sequence for rotation periods between 5-25 days.
Unfortunately, the total observing time is too short to draw sound conclusions
on activity cycles with similar length as the solar cycle.

18
The categories of this paper are: econ
28
The categories of this paper are: alg-geom
9
The categories of this paper are: nlin
20
The categories of this paper are: acc-phys
8
The categories of this paper are: hep-ex
24
The categories of this paper are: dg-ga
13
The categories of this paper are: quant-ph
3
The categories of this paper are: physics
30
The categories of this paper are: q-alg
37
The categories of this paper are: supr-con
17
The categories of this paper are: q-fin
36
The categories of this paper are: cmp-lg
16
The categories of this paper are: stat
1
The categories of this paper are: cs
29
The categories of this paper are: funct-an
14
The categories of this paper are: math-ph