Frankfurt Quasar Monitoring


B2 1147+24
Object data

  Cross-Identifications   OM+280, TXS 1147+245, S3 1147+24, B2 1147+24
  SDSS J115019.21+241753.8, 1FGL J1150.2+2419
  7C 1147+2434, GALEXASC J115019.23+241754.3
  2E 1147.7+2435, FBQS J115019.2+241753

  Equat. coordinates   RA  11 50 19.2     DE  +24 17 54      (J2000)
  Constellation   Leo
  Type   BL Lac
  Redshift (2)   z=0.200
  Distance (2) (3)
  791 Mpc
  Total mag range (mv) (4)   13.7 - 17.0
  Catalog Magnitude   15.74 (1)  /  17.57 (2)
  Absolute Magnitude (1)   --- MB
  Light Travel-Time (2)   2.353 × 109 yrs
(1) Véron-Cetty & Véron 2006, A&A 455, 776
(2) NASA/IPAC Extragalactic Database
(3) Co-Moving Radial Distance
(4) Literature

Finding chart

1147+245_chart_fqm.jpg


Comparison stars
star V Rc Ic
C1 12.52 (0.05)
12.18 (0.05)
11.81 (0.05)
C2 12.68 (0.05)
12.32 (0.05)
11.94 (0.05)
C3 13.13 (0.05)
12.78 (0.06)
12.47 (0.06)
C4 13.68 (0.06)
13.18 (0.06)
12.64 (0.06)
comparison stars from Fiorucci et al. 1996, A&AS, 116, 403

Colour chart

1147+245_color_fqm.jpg
Credit: SDSS  /  Size 13´× 13´ /  Chart by S. Karge

Light curve

1147+245_lc2301_fqm.jpg

  Notes
B2 1147+24 (= OM 280) is a variable BL Lac object in north-eastern Leo, close to the constellation Coma Berenices. B2 1147+24 was discovered as a flat-spectrum radio source in the late 1960s by the Bologna Radio Survey (B2) and the Ohio Radio Survey (OM). Since then, it has been catalogued by various other radio surveys. Spectroscopic investigations during the mid 1970s revealed a continuous spectrum. Together with its optical polarization it was classified as a BL Lac object. Despite its featureless spectrum, a redshift of z=0.200 was derived from the fact, that the source is optically unresolved, suggesting z > 0.2. The FR2 radio morphology also suggests that it is a high-z object. That is why no redshift is given in the quasar catalogs by Véron-Cetty & Veron (2001-2010).

B2 1147+24 is a variable object with a total optical range of about 3 magnitudes.
CCD observers, as well as visual observers, shall use the comparison stars given above. The comparison stars C1=12.52 and C2=12.68 are recommended for both unfiltered and v-mag photometry. B2 1147+24 remains about mag-16 for most of the time, so visual observers need at least a 14- to 16-inch telescope to glimpse this stellar object.
____________

Observers who like to continue their observing session with more quasi-stellar photons may turn to quasar PG 1116+215, a bright 14-mag object at a distance of about 2×109 light-years, 7.7° WSW of B2:1147+24. Another highly variable BL Lac object is W Com, located 8° NE.

About 6° E of
B2 1147+24 we find the naked eye open cluster Mel 111, the Coma Cluster, as well as some bright galaxies of the Coma I-cluster, like NGC 4565, NGC 4494 and NGC 4559. Visual observers may also like to take a look at two loose galaxy groups in western Leo: The NGC 3607-galaxy group (10° SW) and the NGC 3684-galaxy group (8.8° SW). Finally, rich galaxy cluster Abell 1367 (4.6° SSW), dominated by its cD-galaxy NGC 3842, shall not be missed.


Literature
Angel, J.R.P., Stockman, H.S. 1980, ARA&A, 18, 321; Optical and infrared polarization of active extragalactic
     objects.
Colla, G., Fanti, C., et al. 1972, A&AS, 7, 1; The B2 Catalogue of radio sources - second part.
Dixon, R.S., Kraus, J.D. 1968, AJ, 73, 381; A High-Sensivity 1415 MHz Survey at North Declinations between
     19 and 37 degrees.
Fiorucci, M., Tosti, G. 1996, A&AS, 116, 403; VRI photometry of stars in the fields of 12 BL Lacertae objects.
Fiorucci, M., Tosti, G. 1996, A&AS, 117, 475; Automatic optical monitoring of 10 Blazars.
Katajainen, S., Takalo, L.O., et al. 2000, A&AS, 143, 357; Tuorla quasar monitoring I. Observations of 1995-1997.
Kinman, T.D. 1976, ApJ, 205, 1; Photoelectric Magnitudes and Polarization Data for possible BL Lacertae Objects.
Moles, M., Garcia-Pelayo, J.M., Masegosa, J., Aparicio, A. 1985, ApJS, 58, 255; BVRI observations of BL Lacertae
     objects.
Pica, A.J., Smith, A.G., et al. 1988, AJ, 96, 1215; Long-term optical behavior of 144 compact extragalactic objects -
     1969-1988.
Rector, T.A., Stocke, J.T. 2001, AJ, 122, 565; The Properties of the Radio-Selected 1 Jy Sample of BL Lacertae
     Objects.
Sowards-Emmerd, D., Romani, R.W., et al. 2005, ApJ, 626, 95; Northern Survey of Gamma-Ray Blazar Candidates.
Steinicke, W.; Katalog heller Quasare und BL Lacertae Objekte; Umkirch 1998.
Stickel, M., Fried, J.W., Kühr, H. 1993, A&AS, 98, 393; The complete sample of 1 Jy BL Lac objects. II.
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.
Wills, D., Wills, B.J. 1976, ApJS, 31, 143; Spectroscopy of 206 QSO candidates and radio galaxies.
Zekl, H., Klare, G., Appenzeller, I. 1981, A&A, 103, 342; Optical Brightness Variations of BL-Lacertae Objects.




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© Stefan Karge  /  last obs. 2023-01-18
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