Relativistic amplification boosts the contribution of the jet base to the total emission in blazars , thus making single dish observations useful and practical to characterise their physical state , particularly during episodes of enhanced multi-wavelength activity .
Following the detection of a new gamma-ray source by Fermi -LAT in July 2017 , we observed S4 0444+63 in order to secure its identification as a gamma-ray blazar .
We conducted observations with the Medicina and Noto radio telescopes at 5 , 8 , and 24 GHz for a total of 12 epochs between 2017 August 1 and 2018 September 22 .
We carried out the observations with on-the-fly cross scans and reduced the data with our newly developed Cross-scan Analysis Pipeline , which we present here in detail for the first time .
We found the source to be in an elevated state of emission at radio wavelength , compared to historical values , which lasted for several months .
The maximum luminosity was reached on 2018 May 16 at 24 GHz , with L _ { 24 } = ( 1.7 \pm 0.3 ) \times 10 ^ { 27 } \mathrm { W Hz } ^ { -1 } ; the spectral index was found to evolve from slightly rising to slightly steep .
Besides the new observations , which have proved to be an effective and efficient tool to secure the identification of the source , additional single dish and very-long-baseline interferometry data provide further insight on the physics of the source .
We estimate a synchrotron peak frequency \nu _ { \mathrm { peak } } = 10 ^ { 12.97 } Hz and a Doppler factor in excess of \delta \sim 5.0 , with both quantities playing a role in the gamma-ray emission from the source .