Frankfurt Quasar Monitoring


AP Lib = PKS 1514-24
Object data

  Cross-Identifications  OR-225, PKS 1514-24, TXS 1514-241, QSO B1514-24
  ESO 514-G01, PGC 54592, LEDA 54592, 1514-241
  WMAP J1517-2421, 2MASX J15174180-2422192
  1E 1514.7-2411, RX J1517.6-2422

  Equat. coordinates   RA  15 17 41.8     DE  -24 22 20     (J2000)
  Constellation   Libra
  Type   BL Lac
  Redshift (2)   z=0.049
  Distance (2) (3)   202 Mpc
  Total mag range (mv) (4)   13.4 - 16.7
  Catalog Magnitude (1)   14.80
  Absolute Magnitude (1)   -21.7 MB
  Light Travel-Time (2)   0.642 × 109 yrs
(1) Véron-Cetty & Véron 2006, A&A 455, 776
(2) NASA/IPAC Extragalactic Database
(3) Metric Distance
(4) Literature


Finding chart
1514-241_chart_fqm.jpg

Comparison stars

star U B V Rc Ic
1 ---- 14.582 (0.023)
13.746 (0.003)
13.277 (0.002)
12.878 (0.040)
2 16.069 (0.100) 15.583 (0.013)
14.673 (0.004)
14.190 (0.014)
13.805 (0.023)
6 ---- 16.598 (0.069)
15.555 (0.033)
14.870 (0.020)
14.281 (0.024)
7 17.487 (0.369) 17.427 (0.048)
16.387 (0.017)
15.789 (0.011)
15.267 (0.028)
10 14.850 (0.037) 14.527 (0.020)
13.647 (0.003)
13.095 (0.033)
12.637 (0.067)
12 ---- 17.919 (0.189)
17.221 (0.047)
16.084 (0.030)
----
15 16.402 (0.148) 16.831 (0.031)
16.059 (0.027)
15.613 (0.028)
15.212 (0.026)
16 16.760 (0.199) 16.991 (0.033)
16.210 (0.014)
15.680 (0.020)
15.211 (0.036)
18 ---- 16.523 (0.068)
15.805 (0.021)
15.277 (0.015)
14.914 (0.038)
Selected comparison stars from Gonzŕlez-Pérez et al. 2001, AJ, 122, 205

Colour chart
1514-241_color_fqm.jpg
Credit: DSS2  /  Size 14´× 14´ /  Chart by S. Karge

Light curve
1514-241_lc2301_fqm.jpg

Notes
AP Lib = PKS 1514-24 is a variable BL Lacertae object in southern Libra, some 3° NE of Sigma Librae. The designation AP Lib indicates that this object was initially discovered as a variable star. Indeed, Martha Ashbrook from Harvard College Observatory discovered this variable object in 1942. She recognized this object due to its optical variability on Harvard photographic plates, taken between 1935 and 1942. This new variable was designated AP Lib, and was later included in the GCVS. At the position of AP Lib, a flat spectrum radio source was detected during Parkes Radio Survey in 1965, and soon identified with an elliptical galaxy, that shows an apparent diameter of 0.5´× 0.4´. In 1971, this elliptical was matched with AP Lib. The host of AP Lib was classified as an N-galaxy by spectroscopy.
Despite
its nearly featureless spectrum, a redshift was determined in 1974. Based on the flux variability and the optical polarization, AP Lib was classified as a BL Lacertae object. The faint lenticular galaxy, only 1`NE, has the same distance as AP Lib and is supposed to be associated with the BL Lac host - possibly triggering the AGN activity of AP Lib due to tidal interaction.

AP Lib is a large amplitude variable object with a total range of about 3 magnitudes in the optical.
Visual observers need at least a 12- to 14-inch telescope to glimpse this stellar object. Observers using large aperture telescopes with higher power may recognize the object becoming increasingly star-like, a clear sign of the host.
For mid-northern observers, this object is of course a challenge due to its southern declination. CCD observers, as well as visual observers, shall use the comparison stars given above. Another sequence was published by the AAVSO.
____________

Point your telescope 3.3° to the north to visit NGC 5897, a pretty bright globular cluster of remarkable low concentration (class 11).
Those observers who like to detect more very old quasi-stellar photons may turn to quasar PKS 1510-08, another large amplitude variable object at a distance of about 3.8×109 light-years, some 15° north.


Literature
Ashbrook, M.D. 1942, Harvard Ann., 109, 7; Ninety-nine Variable Stars in Milky Way Field 359.
Biraud, F. 1971, Nature 232, 178; Rapid Optical Variability of the Source PKS 1514-24.
Bolton, J., Clarke, M.E., Ekers, R.D. 1965, AuJPh, 18, 627; Identification of extragalactic radio sources between
     declinations -20° and -44°.
Bond, H.E. 1971, ApJ, 167, 79; The Optically Variable Radio Source PKS 1514-24 = AP Librae.
Disney, M.J., Peterson, B.A., Rodgers, A.W. 1974, ApJ, 194, L79; The redshift and composite nature of AP Librae
     (PKS 1514-24).
Gonzŕlez-Pérez, J.N., et al. 2001, AJ, 122, 2055; Optical and Near-Infrared Calibration of AGN field stars: An All-Sky
     Network of faint stars calibrated on the Landolt System.
Pesce, J.E., Falomo, R., Treves, A. 1994, AJ, 107, 494; Imaging and spectroscopy of galaxies in the fields of five
     BL Laceratae objects.
Pollock, J.T., Pica, A.J., et al. 1979, AJ, 84, 1658; Long-term optical variations of 20 violently variable extragalactic
     radio sources.
Searle, L., Bolton, J. 1968, ApJ, 154, 101L; Redshifts of Fifteen Radio Sources.
Steinicke, W.; Extragalactic Objects Discovered as Variable Stars; Umkirch 2000.
Véron-Cetty, M.-P., Véron, P. 2001, A&A 374, 92; A Catalogue of Quasars and Active Nuclei: 10th edition.
Véron-Cetty, M.-P., Véron, P. 2003, A&A 412, 399; A Catalogue of Quasars and Active Nuclei: 11th edition.
Véron-Cetty, M.-P., Véron, P. 2006, A&A 455, 776; A Catalogue of Quasars and Active Nuclei: 12th edition.
Véron-Cetty, M.-P., Véron, P. 2010, A&A 518, 10; A Catalogue of Quasars and Active Nuclei: 13th edition.
Westerlund, B.E., Wall, J.V. 1969, AJ, 74, 335; Three-color photometry of southern QSO's, radio galaxies, and normal
     galaxies.




Links:

Hamburg Quasar Monitoring

Chara/PEGA

AAVSO


© Stefan Karge  /  last obs. 2023-01-13






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