PKS 1402-012, also known as UM 632, is a quasar located in the constellation of Virgo. With a redshift of 2.51, the object is located 10.7 billion light-years from Earth.[1]
PKS 1402-012 | |
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![]() The quasar PKS 1402-012, seen by DESI Legacy Surveys | |
Observation data (J2000.0 epoch) | |
Constellation | Virgo |
Right ascension | 14h 04m 45.895s |
Declination | -01d 30m 21.947s |
Redshift | 2.518154 |
Heliocentric radial velocity | 754,924 km/s |
Distance | 10.732 Gly (light travel time distance) |
Apparent magnitude (V) | 0.149 |
Apparent magnitude (B) | 0.197 |
Surface brightness | 18.3 |
Characteristics | |
Type | Opt.var, RLQ |
Other designations | |
UM 632, 2QZ J140445.8-013022, PGC 50193, NVSS J140445-013021, QUEST 123404, TXS 1402-012, IRCF J140445.8-013021 |
As one of the objects observed and noted by researchers analyzing the Parkes quarter-Jansky flat-spectrum sample at Parkes Observatory,[2][3] PKS 1402-012 is classified a blazar.[4][5][6] Optically variable,[7] it is a type of active galaxy shooting out an astrophysical jet in the direction of Earth, PKS 1402-012 is found to emit large amounts radiation over the whole electromagnetic spectrum up to TeV energies.[8] It was a target of prior X-ray observations mentioned in the Einstein quasar database[9] and is a high redshift gamma ray loud quasar.[10][11]
PKS 1402-012 is also a BL Lac object[12] and such has a bolometric luminosity of 1044 ≲ L≲ 1048 erg s−1 with a weak emission-line showing EW(C iv)≲10 Å, with a high Eddington ratio, in relationship to the modified Baldwin effect.[13] Like other quasars, PKS 1402-012 has a flux-density distribution and luminosity function stronger than 2.4 mJy[14] The flux-density varies time to time. In 1972, the flux density was at 0.67 Jy with the flux-density decreasing to 0.15 Jy in 1989.[15]
The host galaxy of PKS 1402-012 is a massive starburst early-type galaxy, located inside an overdense rich galaxy cluster at a >=2σ level.[16] It is found amidst a violent star-forming event, producing a significant fraction of stars within 0.5 billion years[17] and large quantities of high-density ionized gas in its regions.[18] The quasar contains an extragalactic radio source,[19] which is responsible for powering strong star formations with rates of ~500 M_sun per year, consistent with its "quasar mode" accretion in which cold gas flows fuel both the AGN and starburst.[14][20]
According to the Hubble Space Telescope, PKS 1402-012 is a gravitational lensed quasar which researchers noted ground based direct imaging characterized by a good dynamical range is the best observational strategy in the long term.[21][22]
PKS 1402-012 has an absorption-line.[23] In a study of 821 quasars and 8558 absorption-line systems sampled in the quasar spectra, researchers found lines of heavy elements and neutral hydrogen in PKS 1402–012.[24] Apart from that, the quasar also shows evidence of HI 21 cm absorption,[25] is a strong C IV absorber stronger EWrest>=0.5 Å[26] and a damped Lyman α (DLA) system, containing ~90 per cent of the neutral HI mass.[27][28]
Through observation by researchers for its spectral line equivalent widths, the quasar also contains O [III] narrow lines and C IV λ1549 and Mg II λ2799 broad lines, correlating positively with R I at 4σ-8σ level but no strong depended on R suggesting the line-of-sight angle to the radio-jet axis of PKS 1402-012 decreases.[29] Furthermore, they found Ca ii absorbers with a rest frame equaling to widths of Wr,3934 = 15-799 mÅ and column density of log N(Ca ii) = 11.25-13.04, following a steep power law pattern of, f(N) ∝ N - β and slope angle - β = -1.68.[30]
Researchers also detected a 21-cm absorption in Mg ii absorbers of PKS 1402–012. Through results, they found the quasar has a linear size of LS < 100 pc, since its detection rate is higher at cm wavelengths. With a velocity width of ΔV > 100 km s−1, PKS 1402-012 also shows an extended radio morphology at arcsecond scales. Researchers noted the 21-cm detection rate in strong Mg ii systems is constant over 0.5 < zabs < 1.5; that is over ~30% of the total age of universe.[31]
According to researchers who used a mass estimator based on the Hβ, Mg II, and C IV emission lines,[32] they found the supermassive black hole in PKS 1402-012 is found to grow at an exponentially rate with a solar mass range estimated 108.8-1010.7 Msolar and high luminosity of 1045.2<λLλ(5100 Å)<1047.3 ergs s−1.[33]
The growth rate of the black hole is found longer compared to the age of the universe with a corresponding epoch, suggesting there was an earlier episode of faster growth at z >~3.[33]
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