Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: An Empirical Study of Contamination in Deep, Rapid, and Wide-Field
  Optical Follow-Up of Gravitational Wave Events   We present an empirical study of contamination in deep, rapid, and wide-field
optical follow-up searches of GW sources from aLIGO. We utilize dedicated
observations during four nights of imaging with DECam. Our search covered
$\sim56$ deg$^2$, with two visits per night separated by $\approx 3$~hours, in
$i$- and $z$-band, followed by an additional set of $griz$ images three weeks
later to serve as reference images for subtraction, and for the purpose of
identifying galaxy and stellar counterparts for any transient sources. We
achieve $5\sigma$ point-source limiting magnitudes of $i \approx 23.5$ and $z
\approx 22.4$ mag in the coadded single-epoch images. We conduct a search for
transient objects that can mimic the $i-z$ color behavior of both red ($i-z >
0.5$~mag) and blue ($i-z < 0$~mag) kilonova emission, finding 11 and 10
contaminants, respectively. Independent of color, we identify 48 transients of
interest. Additionally, we leverage the rapid cadence of our observations to
search for sources with characteristic timescales of $\approx1$ day and
$\approx3$ hours, finding no potential contaminants. We assess the efficiency
of our pipeline and search methodology with injected point sources, finding
that we are 90\% (60\%) efficient when searching for red (blue) kilonova-like
sources to a limiting magnitude of $i \lesssim 22.5$ mag. Applying these
efficiencies, we derive sky rates for kilonova contaminants in the red and blue
regimes of $\mathcal{R}_{\rm red} \approx 0.16$ deg$^{-2}$ and
$\mathcal{R}_{\rm blue} \approx 0.80$ deg$^{-2}$. The total contamination rate,
independent of color, is $\mathcal{R}_{\rm all} \approx 1.79$ deg$^{-2}$. We
compare our derived results to optical follow-up searches of the GW events
GW150914 and GW151226 and comment on the outlook for GW follow-up searches as
additional GW detectors (e.g., KAGRA, LIGO India) come online in the next
decade.

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The categories of this paper are: chao-dyn
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The categories of this paper are: supr-con
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The categories of this paper are: q-fin
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The categories of this paper are: nlin
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The categories of this paper are: ao-sci
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The categories of this paper are: stat
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The categories of this paper are: physics
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The categories of this paper are: math
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The categories of this paper are: alg-geom
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The categories of this paper are: quant-ph
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The categories of this paper are: bayes-an
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The categories of this paper are: econ
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The categories of this paper are: hep-ex
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The categories of this paper are: eess
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The categories of this paper are: math-ph
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The categories of this paper are: hep-lat