The intra-day Optical Monitoring of BL Lacerate Object 1ES 1218+304 at Its Highest X-ray Flux Level. (arXiv:2104.00920v1 [astro-ph.GA])
<a href="http://arxiv.org/find/astro-ph/1/au:+Sun_S/0/1/0/all/0/1">S.S. Sun</a> (1,2), <a href="http://arxiv.org/find/astro-ph/1/au:+Li_H/0/1/0/all/0/1">H.L. Li</a> (2,3), <a href="http://arxiv.org/find/astro-ph/1/au:+Yang_X/0/1/0/all/0/1">X. Yang</a> (1), <a href="http://arxiv.org/find/astro-ph/1/au:+Lu_J/0/1/0/all/0/1">J. Lü</a> (1), <a href="http://arxiv.org/find/astro-ph/1/au:+Xu_D/0/1/0/all/0/1">D.W. Xu</a> (2,3), <a href="http://arxiv.org/find/astro-ph/1/au:+Wang_J/0/1/0/all/0/1">J.Wang</a> (1,2) ((1) Guangxi key Laboratory for Relativistic Astrophysics, Guangxi University, (2) Key Laboratory of Space Astronomy and Technology National Astronomical Observatories, Chinese Academy of Science,(3) School of Astronomy and Space Science, University of Chinese Academy of Science)
We here report a monitor of the BL Lac object 1ES 1218+304 in both B- and
R-bands by the GWAC-F60A telescope in eight nights, when it was triggerd to be
at its highest X-ray flux in history by the VERITAS Observatory and Swift
follow-ups. Both ANOVA and $chi^2$-test enable us to clearly reveal an
intra-day variability in optical wavelengths in seven out of the eight nights.
A bluer-when-brighter chromatic relationship has been clearly identified in
five out of the eight nights, which can be well explained by the shock-in-jet
model. In addtion, a quasi-periodic oscilation phenomenon in both bands could
be tentatively identified in the first night. A positive delay between the two
bands has been revealed in three out of the eight nights, and a negative one in
the other nights. The identfied minimum time delay enables us to estimate the
$M_{mathrm{BH}}=2.8times10^7 rm M_{odot}$that is invalid.
We here report a monitor of the BL Lac object 1ES 1218+304 in both B- and
R-bands by the GWAC-F60A telescope in eight nights, when it was triggerd to be
at its highest X-ray flux in history by the VERITAS Observatory and Swift
follow-ups. Both ANOVA and $chi^2$-test enable us to clearly reveal an
intra-day variability in optical wavelengths in seven out of the eight nights.
A bluer-when-brighter chromatic relationship has been clearly identified in
five out of the eight nights, which can be well explained by the shock-in-jet
model. In addtion, a quasi-periodic oscilation phenomenon in both bands could
be tentatively identified in the first night. A positive delay between the two
bands has been revealed in three out of the eight nights, and a negative one in
the other nights. The identfied minimum time delay enables us to estimate the
$M_{mathrm{BH}}=2.8times10^7 rm M_{odot}$that is invalid.
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