Bibcode
Polednikova, J.; Ederoclite, A.; de Diego, J. A.; Cepa, J.; González-Serrano, J. I.; Bongiovanni, A.; Oteo, I.; Pérez García, A. M.; Pérez-Martínez, R.; Pintos-Castro, I.; Ramón-Pérez, M.; Sánchez-Portal, M.
Bibliographical reference
Monthly Notices of the Royal Astronomical Society, Volume 460, Issue 4, p.3950-3959
Advertised on:
8
2016
Citations
11
Refereed citations
11
Description
Microvariability (intranight variability) is a low amplitude flux change
at short time-scales (i.e. hours). It has been detected in unobscured
type 1 active galactic nuclei (AGN) and blazars. However in type 2 AGN,
the detection is hampered by the low contrast between the presumably
variable nucleus and the host galaxy. In this paper, we present a search
for microvariability in a sample of four type 2 quasars as an
astrostatistical problem. We are exploring the use of a newly introduced
enhanced F-test, proposed by Diego. The presented results show that out
of four observed target, we are able to apply this statistical method to
three of them. Evidence of microvariations is clear in the case of
quasar J0802+2552 in all used filters (g', r' and i') during both
observing nights, and they are present in one of the nights of
observations, J1258+5239 in one filter (i'), while for the J1316+4452,
there is evidence for microvariability within our detection levels
during one night and two filters (r' and i'). We demonstrate the
feasibility of the enhanced F-test to detect microvariability in
obscured type 2 quasars. At the end of this paper, we discuss possible
causes of microvariability. One of the options is the misclassification
of the targets. A likely scenario for explanation of the phenomenon
involves optically thin gaps in a clumpy obscuring medium, in accordance
with the present view of the circumnuclear medium. There is a possible
interesting connection between the merging state of the targets and
detection of microvariability.