PKS 0537-441 | |
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![]() The blazar PKS 0537-441 | |
Observation data (J2000.0 epoch) | |
Constellation | Pictor |
Right ascension | 05h 38m 50.361s |
Declination | −44° 05′ 08.939″ |
Redshift | 0.896000 |
Heliocentric radial velocity | 268,614 km/s |
Distance | 7.335 Gly |
Apparent magnitude (V) | 16.48 |
Apparent magnitude (B) | 15.77 |
Characteristics | |
Type | Blazar, BL Lac |
Other designations | |
LEDA 2824444, IRAS F05373-4406, WMAP 148, 4FGL J0538.8-4405, 2E 1488, Cul 0537-441 |
PKS 0537-441 is a blazar [1] located in the constellation of Pictor. It has a redshift of 0.896 [2] and was discovered in 1973 by an American astronomer named Olin J. Eggen, who noted it as a luminous quasar. [3] This is a BL Lacertae object in literature because of its featureless optical spectra [4] [5] as well as both a possible gravitational microlensing [6] and a gravitationally lensed candidate. [7] Its radio source is found compact and is characterized by a spectral peak in the gigahertz range, making it a gigahertz-peaked spectrum source (GPS). [8]
PKS 0537-441 is found violently variable on the electromagnetic spectrum at all frequencies, [9] and is a source of gamma ray emission. [10] [11] Between December 2004 and March 2005, it underwent intense activity showing more than 4 magnitudes in a V filter in 50 days and 2.5 in 10 days. [12] PKS 0537-441 is also known to display two flaring episodes, one in July 2009 and one in March 2010, with its gamma ray luminosity in the 0.1-100 GeV energy range reaching a peak value (2.6 x 1048 erg s−1) on 3-d timescales at the end of the month. [13] During its variability, PKS 0537-441 shows signs of both flux and color index variability on timescales. [14]
PKS 0537-441 contains a radio structure. The source is found to be core dominated on arcsecond scales with a secondary bright component separated by 7".2 at a 305° positional angle (PA). However, according to 2.3 GHz observations conducted by the Southern Hemisphere VLBI Experimental program (SHEVE), the radio structure has a 4.2 Jansky core with a measured diameter of 1.1 mas. There is a jetlike component, confirmed to be an asymmetric core-jet structure according to a 5 GHz Very-long-baseline interferometry imaging. This component is located north of the compact core. [15]
PKS 0537-441 shows gamma ray and optical oscillations. During its high state between August 2008 and 2011, the periodogram of its gamma ray light curve displays a peak reaching T0 ~ 280 days with significance of 99.7%. [16] A broad magnesium ionized emission line was also discovered at redshift (z) 0.885, implied to be a mini low ionization broad absorption-line quasar. This speculates PKS 0537-441 might be a binary quasar. [17]