Active galactic nucleus in the constellation Libra
AP Librae
Light curves for AP Librae. Top panel: The long-term variability, plotted from data published by Fan & Lin (2000).[1] Bottom panel: short-timescale variability, adapted from Cariniet al. (1991)[2]
This object was first identified as an opticalvariable by Martha D. Ashbrook in 1942, who noted the brightness changed irregularly from magnitude 15.0 down to 16.0.[11] The source was found to vary chaotically on time scales of days and even hours.[12] Howard E. Bond and Francois Biraud in 1971 noted the coincidence of this object with the position of theradio source PKS 1514–24.[13] In 1965,John G. Bolton and associates identified the latter as a sixteenth magnitudeelliptical galaxy.[11] Glenn M. Frye and associates in 1971 suggested that it may be agamma-ray source.[13] The similarity of this object toBL Lacertae was noted, leading to it being designated as a BL Lac object.[14]
AP Librae emits asynchrotron radiation component to itsspectral energy distribution (SED). The peak component of this radiation lies in theinfrared band, making this a low-frequency peaked BL Lac (LBL). It is one of the few LBLs known to emit gamma rays. The width of the high energy component of the SED is considered extremely broad for objects of this class, ranging in energy from around0.1 keV up to the TeV level.[15] In 1998–99, extended radio emission was detected from a one-sidedjet that starts in a south-easterly direction from the source before bending to the northeast.[16] This non-thermal jet extends15″ from AP Lib (equivalent to ~46 kly), and in 2013 was found to emitX-rays.[10] The jet may be the source for the gamma-ray emission in the TeV range.[17]
^Ducati, J. R. (2002), "VizieR Online Data Catalog: Catalogue of Stellar Photometry in Johnson's 11-color system.",CDS/ADC Collection of Electronic Catalogues, vol. 2237, no. 2237,Bibcode:2002yCat.2237....0D.
Meyer, E.; et al. (January 2021), "What is the origin of the VHE emission in AP Librae?",Bulletin of the American Astronomical Society,53 (1),Bibcode:2021AAS...23723805M, 2021n1i238p05.
Zacharias, Michael; Wagner, Stefan J. (January 2017), "The extended jet in AP Librae as the source of the VHE γ-ray emission",6th International Symposium on High Energy Gamma-Ray Astronomy, AIP Conference Proceedings,1792 (1): 050014,arXiv:1611.02103,Bibcode:2017AIPC.1792e0014Z,doi:10.1063/1.4968960,S2CID9135990, 050014.
Petropoulou, M.; et al. (January 2017), "The TeV emission of Ap Librae: a hadronic interpretation and prospects for CTA",Monthly Notices of the Royal Astronomical Society,464 (2):2213–2222,arXiv:1608.07300,Bibcode:2017MNRAS.464.2213P,doi:10.1093/mnras/stw2453.
Ciprini, Stefano (August 2016), "Fermi LAT detection of a GeV gamma-ray flare from the BL Lac object AP Librae",The Astronomer's Telegram,9442 (9442): 1,Bibcode:2016ATel.9442....1C.
Sanchez, David; et al. (August 2012), "The challenging SED of AP Librae",The Spectral Energy Distribution of Galaxies, Proceedings of the International Astronomical Union, IAU Symposium, vol. 284, pp. 411–413,Bibcode:2012IAUS..284..411S,doi:10.1017/S1743921312009532.
Gudkova, Diana; et al. (November 2009), "The Optical Variability of PKS 1510-089, PKS 1622-297 and AP Librae",American Physical Society, 76th Annual Meeting of the Southeastern Section of APS, November 11-13, 2009, vol. 76,Bibcode:2009APS..SES.PB002G, PB.002.
Baxter, D. A.; et al. (September 1987), "Photometric analysis and decomposition of AP Librae (PKS 1514-24).",Monthly Notices of the Royal Astronomical Society,228 (2):313–327,Bibcode:1987MNRAS.228..313B,doi:10.1093/mnras/228.2.313.
Westerlund, B. E.; et al. (January 1982), "The properties of AP Lib from UBV photoelectric photometry",Astronomy and Astrophysics,105:284–292,Bibcode:1982A&A...105..284W.
Capps, R. W.; Knacke, R. F. (1978), "Polarization of 3C 371 and AP Librae at 2.2μm",Astrophysical Letters,19: 113,Bibcode:1978ApL....19..113C.
Disney, M. J.; et al. (December 1974), "The Redshift and Composite Nature of AP Librae (pks 1514-24)",Astrophysical Journal,194: L79,Bibcode:1974ApJ...194L..79D,doi:10.1086/181673.
Miller, H. R.; Clonts, S. L.; Folsom, G. H. (December 1974), "Rapid optical variability of the extragalactic radio source PKS 1514-24",Astronomical Journal,79: 1352,Bibcode:1974AJ.....79.1352M,doi:10.1086/111685
