PKS 1144-379 also known asPKS B1144-379, is aquasar located in the constellation ofCentaurus. At theredshift of 1.048,[1] the object is located nearly 8 billionlight-years fromEarth.[2]
PKS 1144-379 is classified as a flat-spectrum radio quasar (FSRQ), brighter than S4.8 GHz=65 mJy.[3][4] It has anactive galactic nucleus with highoptical polarization.[5][6] As monitored at 13 cm and 6 cm by researchers over three years, which they found it as a star-like object, PKS 1144-379 has been identified asBL lac object[7] of Mv ≈16.2, due to its variability in optical,infrared, and radiowavelengths.[8][1] Such BL Lac objects like PKS 1144-379 are rare active galactic nuclei class, characterized by allfrequencies, and absence ofemission lines.[9]
PKS 1144-379 is also radio variable as observed in the Parkes 2700 MHz survey by researchers working atParkes Observatory.[10] The quasar is dominated by its bright compact radio core, but according to maps that is made with a highdynamic range, it shows an extended structure. PKS 1144-379 also has aluminosity above both FR I/FR II limit ~ 1032 erg s−1 Hz−1 at 5 GHz[11] and such also classfied as ablazar,[12][13] a type ofactive galaxy that is producingradiation, observed at wavelengths from radio togamma rays.[14]
PKS 1144-379 is known to be variable for its long and short-termflux density variability atcentimeter wavelengths. Some of the first observations of PKS 1144−379 showed variability atfrequencies of 5 GHz. The flux density is shown to increase from 0.9 Jy to 1.6 Jy between December 1970 and February, 1971.[15][16] In September of the same year, it had increased again to 2.22 Jy.[17] Between May and August 1994, the flux density of PKS 1144−379 at 4.8GHz dropped by 17%, and subsequently 9% at 8.6 GHz.[18]
In June 1996, PKS 1144-379 underwent optical variation again. Over the next 2.5 days, thesurvey data shows the quasar had a 33% change at 4.8GHz. Subsequent data showed more variations in PKS 1144–379 with maximum of 8.6 GHz with over three hours of irregular change of 20%. This is strongly correlated with 10% change at 4.8 GHz.[19] From the results studying the variability behavior of PKS 1144–379, researchers found the optical variation is 1.92 mag. This is smaller than those, ~ 3.5 mag in its infrared region.[20]
Using the Ceduna 30-m radiotelescope at a frequency of 6.7 GHz and verylong baseline interferometry (VLBI) data at 8.6 GHz at theUniversity of Tasmania inAustralia, researchers investigated the evolution of PKS 1144–379. They found the variability time-scales associated with twoflares detected in PKS 1144-379 between November 2005 and August 2008 were found to derive from long-term variations in totalflux density as monitored by Ceduna between 2003 and 2011. Moreover, a kinematic study of the parsec-scale jet of PKS 1144-379 was also performed through VLBI data obtained between 1997 and 2018, which they observe quasi-periodic flarings of ~3-4 yr. Over the 20-yr interval, they found the average jetposition angle was ~150°.[21] The core component of PKS 1144-379 is found to be compacted, which itsangular size varied between the ranges of 5.65-15.90 Чas estimating to be 0.05-0.13 pc.[22]
Researchers assumed the variations observed in PKS 1144–379, are due toscintillation. The variations are 6.2 ×1012 K at 4.9 GHz with approximately 10% of total flux density found in the scintillating component. Given the results, PKS 1144-379 has a highmodulation index in the range of 5–18%[22] combined with the 1.2 day characteristic timescale (corresponding to a peak-to-peak period of 7.7 days), making it the most extreme brightscintillators identified in history.[23]According toobservations byFermi, PKS 1144-379 has a column dissipationradius of 64.5 x 1015 cm (430)RS with anaccretion disc luminosity of 1045 erg s−1 3 x (0.04)LEdd. The jet power as the form of radiation for the quasar has alog probability of 44.92 logPr withPoynting flux of 44.49 logPB while thebulk motion ofelectrons andprotons is found to be 44.34 logPe and 46.41 logPp. From the results, PKS 1144-379 has an estimatedblack holemass of 108–109 M⊙, whom researchers noted.[24]
^Kedziora-Chudczer, L. L.; Jauncey, D. L.; Wieringa, M. H.; Reynolds, J. E.; Tzioumis, A. K. (1998)."1998ASPC..144..271K Page 271".IAU Colloq. 164: Radio Emission from Galactic and Extragalactic Compact Sources.144: 271.Bibcode:1998ASPC..144..271K. Retrieved2024-06-08.
