G. Calderone, G. Ghisellini, M. Colpi, M. Dotti
B2 0954+25A, detected by the {\it Fermi} satellite, is a blazar with
interesting observational properties: it has been observed to transit from a
jet dominated to a disk dominated state; its radio spectrum appears flat at all
observing frequencies (down to 74 MHz); optically, the H$\beta$ line profile is
asymmetric. The flatness of radio spectrum suggests that the isotropic emission
from radio lobes is very weak, despite the large size of its jet ($\gtrsim$ 500
kpc). Its broad--band spectral energy distribution is surprisingly similar to
that of the prototypical $\gamma$--ray, radio loud, Narrow Line Seyfert 1
($\gamma$--NLS1) galaxy PMN J0948+0022. In this work we revisit the mass
estimates of B2 0954+25A considering only the symmetric component of the
H$\beta$ line and find (1--3) $\times 10^8$ M$_{\sun}$. In light of our
composite analysis, we propose to classify the source as a transition object
between the class of Flat Spectrum Radio Quasar and $\gamma$--ray, radio loud
NLS1. A comparison with two members of each class (3C 273 and PMN J0948+0022)
is discussed.
View original:
http://arxiv.org/abs/1202.3790
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