PKS 0215+015 is classified as a bona fide BL Lac object, displaying typical characteristics such as weak emission lines and high rapidpolarization changes.[8] It is variable on theelectromagnetic spectrum with its optical band displaying variations of more than 4magnitudes.[9] Rapid polarization swings at 50° and -100° were found associated with the rapid flux variations of the object.[10]
According tooptical continuum observations, PKS 0215+015 is found to undergo a flaring period, brightening up to 1.5 magnitude by September 10, 1980.[11] On October 20, 1984, the object reached its brightest state with aB magnitude of 14.5 while its faintest state was recorded on August 11, 1983. By 1986, its brightness flared up once more after being in a faint state in 1985.[12] Observations by theAustralia Telescope Compact Array (ATCA), also showed the source had a strong long-term increase in itsflux density since May 2021.[13]
The radio structure of PKS 0215+015 is compact. Based on radio observations, the source has an invertedspectrum which peaks over 10GHz.[3] It has a radio core which has a highbrightness temperature.[14]Very Large Array imaging showed there is also a bentjet pointing in a north to south direction near the core region, with a subsequent bend clearly shown pointing east.[15] The jet also has a component visible at 2 centimeter and 7 millimeter wavelength imaging which in turn is blended partially with the core.[16]
In February 2022, theIceCube Neutrino Observatory detected a new candidate high-track energymuon neutrino event. DubbedIceCube-220225A, it was found to be associated with PKS 0215+015 which at that time, was undergoing a powerful radio flare exceeding flux densities of 3Jy at bothcentimeter andmillimeter wavelengths.[6] Observations also suggested the neutrino production happened closer to the core.[16]
^Eppel, F.; Kadler, M.; Ros, E.; Benke, P.; Giroletti, M.; Hessdoerfer, J.; McBride, F.; Roesch, F. (2023-08-08),VLBI Probes of Jet Physics in Neutrino-Candidate Blazars,arXiv:2308.04311
^abEppel, F.; Kadler, M.; Ros, E.; Roesch, F.; Hessdoerfer, J.; Benke, P.; Edwards, P. G.; Fromm, C. M.; Giroletti, M. (2023-02-24), "VLBI Scrutiny of a New Neutrino-Blazar Multiwavelength-Flare Coincidence",The Multimessenger Chakra of Blazar Jets,375: 91,arXiv:2301.13859,Bibcode:2023IAUS..375...91E,doi:10.1017/S1743921323000893
