Frankfurt Quasar Monitoring

MRK 180
Object data

  Cross-Identifications   PGC 35899, VII Zw 412, ZWG 334.43, 1133+704
  TXS 1133+704, RGB J1136+701, GB6 J1136+7009
  CGPG 1133.5+7027, 2MASX J11362642+7009268
  S5 1133+70, QSO B1133+704, RX J1136.5+7009
  RBS 1002, XSS J11349+6944, 1E 1133.5+7026
  7C 113332.70+702557.00, 1FGL J1136.6+7009
  1ES 1133+704, RX J1136.5+7009
  Equat. coordinates   RA  11 36 26.5     DE  +70 09 28     (J2000)
  Constellation   Draco
  Type   BL Lac
  Redshift (1)   z=0.046
  Distance (2) (3)    185 Mpc
  Total mag range (mv) (4)   14.3 - 15.4
  Catalog Magnitude (1)   14.49
  Absolute Magnitude (1)   -22.1 MB
  Light Travel-Time (2)   0.591 × 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


Comparison stars

star  B V Rc
1 14.49 (0.02)
13.98 (0.02)
13.73 (0.02)
2 15.36 (0.03)
14.80 (0.02)
14.41 (0.02)
3 16.13 (0.04)
15.49 (0.04)
15.13 (0.02)
4 16.55 (0.03)
16.00 (0.03)
15.66 (0.04)
comparison stars from Villata et al. 1998, A&AS, 130, 305

MRK 180: High resolution images 

Credit: DSS2R / Size 4´× 4´
Reduced contrast shows the
star-like nucleus of MRK 180
(arrow), together
comparison stars #1 and #3
Credit: DSS2B / Size 4´× 4´
The same field section:
contrast shows
elliptical host galaxy
(phot. diam. 0.7´× 0.5´)
Credit: Nilsson et al. (2003)
The host galaxy of MRK 180:
High resolution R-band image
by the Nordic Optical Telescope
  (image size 56.9" × 56.9")


Light curve


Markarian 180 (MRK 180 for short) is a bright BL Lac object in the eastern part of Draco, only about 1° N of Lamda Draconis. The host galaxy (PGC) is thought to be an elliptical galaxy with an apparent diameter of 0.7´× 0.5´ (see images above). MRK 180 was discovered by swiss-born astronomer Fritz Zwicky (Zw), who described it as a "red fuzzy sperical compact, in contact with star or very compact spiral". The designation MRK 180 refers to the UV-Continuum-Survey run by Markarian et al. (MRK), searching for blue galaxies with excessive UV-emission. In 1976, MRK 180 was identified as a BL Lacertae-like object by spectral analysis. Later on, it was found that MRK 180 is also a source of radio emissions (detected by the 5-Ghz Survey (S5)). In addition, MRK 180 is also an emitter of both X-rays (EXOSAT, ROSAT (RX)) and gamma rays (Fermi).

MRK 180 is a small amplitude variable with a total range of about 1 magnitude in the optical. Visual observers with telescopes of 10- to 12-inch of aperture spot a stellar or star-like object at low power. With higher powers, or better with larger apertures, MRK 180 presents itself as a tiny diffuse object with a star-like nucleus. Just 6.3 arcsec south of the nucleus we find a faint star of mag 15.49, earlier described by Zwicky. This star, given as comparison star #3 (see table above), may interfere with the light from MRK 180 during
photometric reduction. CCD observers, as well as visual observers, shall use the comparison stars given above.

Starting our visual trip into the surrounding star field we first meet pretty bright edge-on galaxy NGC 3735, only 30´ N of MRK 180. The nucleus of NGC 3735 shows a Seyfert 2-spectrum, and was therefore classified as an AGN. Turning 3.5° E we find the large 10.7-mag galaxy NGC 4236. But don´t be fooled: what looks like an easy task for telescopes of 8- to 10-inch of aperture turns out to be a tough nut even for large apertures. Actually, NGC 4236 is a low surface brightness galaxy, spreading its faint light over a huge area of 22´× 6´. So you need very dark skies to spot this SBdm-type spiral, a member of the M81-galaxy group.
CCD observers will easily detect the faint edge-on galaxy UGC 6580, some 6 arcmin SE of MRK 180 (see finding chart above). UGC 6580 is a faint B=15.7 mag Sb-c spiral with an apparent diameter of 1.0 × 0.15 arcmin.

Observers who like to track down some more quasi-stellar photons may turn to quasar PG 1351+640, a bright 14-mag object at a distance of about 1.1×109 light-years, some 14.7° ESE of MRK 180.
Finally, another bright 14-mag quasar, PG 0804+761, is located some 15° NW, at a distance of about 1.2×
109 light-years.

Angel, J.R.P., Stockman, H.S. 1980, ARA&A, 18, 321; Optical and infrared polarization of active extragalactic
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.
Markarian, B.E. 1969; Astrofizika 5, 443; Galaxies with Ultraviolet Continuum II.
Moles, M., Garcia-Pelayo, J.M., Masegosa, J., Aparicio, A. 1985, ApJS, 58, 255; BVRI observations of BL Lacertae
Nilsson, K., Pursimo, T., et al. 2003, A&A, 400, 95; R-band imaging of the host galaxies of RGB BL Lacertae objects.
Pica, A.J., Smith, A.G., et al. 1988, AJ, 96, 1215; Long-term optical behavior of 144 compact extragalactic objects -
Rector, T.A., Stocke, J.T. 2001, AJ, 122, 565; The Properties of the Radio-Selected 1 Jy Sample of BL Lacertae
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.
Villata, M., Raiteri, C.M., et al. 1998, A&AS 130, 305; BVR photometry of comparison stars in selected blazar fields,
     I: Photometric sequences for 10 BL Lacertae objects.
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.


Landessternwarte Heidelberg


© Stefan Karge  /  last obs. 2020-01-21