Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Hourly Variability in Q0957+561   We have continued our effort to re-reduce archival Q0957+561 brightness
monitoring data and present results for 1629 R-band images using the methods
for galaxy subtraction and seeing correction reported previously. The new
dataset comes from 4 observing runs, several nights apiece, with sampling of
typically 5 minutes, which allows the first measurement of the structure
function for variations in the R-band from timescales of hours to years.
Comparison of our reductions to previous reductions of the same data, and to
r-band photometry produced at Apache Point Observatory shows good overall
agreement. Two of the data runs, separated by 417 days, permit a sharpened
value for the time delay of 417.4 days, valid only if the time delay is close
to the now-fashionable 417-day value; our data do not constrain a delay if it
is more than three days from this 417-day estimate. Our present results show no
unambiguous signature of the daily microlensing, though a suggestive feature is
found in the data. Both time delay measurement and microlensing searches suffer
from from the lack of sampling at half-day offsets, inevitable at a single
observatory, hence the need for round-the-clock monitoring with participation
by multiple observatories.

34
The categories of this paper are: chem-ph
17
The categories of this paper are: q-fin
23
The categories of this paper are: solv-int
22
The categories of this paper are: chao-dyn
0
The categories of this paper are: hep-ph
36
The categories of this paper are: cmp-lg
1
The categories of this paper are: cs
24
The categories of this paper are: dg-ga
13
The categories of this paper are: quant-ph
7
The categories of this paper are: hep-th
35
The categories of this paper are: mtrl-th
31
The categories of this paper are: ao-sci
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The categories of this paper are: comp-gas
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The categories of this paper are: eess
8
The categories of this paper are: hep-ex
37
The categories of this paper are: supr-con