Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: The Nature of Transition Blazars   Blazars are classically divided into the BL Lac (BLL) and Flat-Spectrum Radio
Quasar (FSRQ) subclasses, corresponding to radiatively inefficient and
efficient accretion regimes, respectively, largely based on the equivalent
width (EW) of their optical broad emission lines (BEL). However, EW-based
classification criteria are not physically motivated, and a few blazars have
previously 'transitioned' from one subclass to the other. We present the first
systematic search for these transition blazars in a sample of 602 unique pairs
of repeat spectra of 354 blazars in SDSS, finding six clear cases. These
transition blazars have bolometric Eddington ratios of ~0.3 and low-frequency
synchrotron peaks, and are thus FSRQ-like. We show that the strong EW
variability (up to an unprecedented factor of >60) is due to swamping of the
BELs from variability in jet continuum emission, which is stronger in amplitude
and shorter in timescale than typical blazars. Although these transition
blazars appear to switch between FSRQ and BLL according to the
phenomenologically-based EW scheme, we show that they are most likely rare
cases of FSRQs with radiatively efficient accretion flows and especially
strongly-beamed jets. These results have implications for the decrease of the
apparent BLL population at high-redshifts, and may add credence to claims of a
negative BLL redshift evolution.

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The categories of this paper are: math
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The categories of this paper are: adap-org
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The categories of this paper are: q-fin
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The categories of this paper are: hep-th
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The categories of this paper are: chao-dyn
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The categories of this paper are: chem-ph
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The categories of this paper are: funct-an
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The categories of this paper are: mtrl-th
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The categories of this paper are: q-alg
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The categories of this paper are: nucl-ex
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The categories of this paper are: hep-ph
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The categories of this paper are: cond-mat
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The categories of this paper are: comp-gas
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The categories of this paper are: bayes-an
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The categories of this paper are: patt-sol
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The categories of this paper are: nlin