Frankfurt Quasar Monitoring

1ES 0806+524
Object data

  Cross-Identifications   RGB J0809+523, QSO B0806+524, 1E 0806+524
  SDSS J080949.18+521858.2, 3EG J0809+5218
  RX J0809.8+5218, 1RXS J080949.2+521855
  1ES 0806+52.4, FIRST J080949.1+521858
  87GB 080601.8+522753, GB6 J0809+5218
  Equat. coordinates   RA  08 09 49.2     DE  +52 18 58     (J2000)
  Constellation   Lynx
  Type   BL Lac
  Redshift   z=0.138
  Distance (2) (3)
  552 Mpc
  Total mag range (mv) (4) (5)   14.8 - 16.3
  Catalog Magnitude (1)   15.3
  Absolute Magnitude (1)   -24.3 MB
  Light Travel-Time (2)   1.687 × 109 yrs
(1) Véron-Cetty & Véron 2006, A&A 455, 776
(2) NASA/IPAC Extragalactic Database
(3) Co-Moving Radial Distance
(4) Literature
(5) Frankfurt Quasar Monitoring

Finding chart


Comparison stars

star V Rc Ic
C1 13.04 (0.05)
12.56 (0.05)
12.14 (0.05)
C2 14.61 (0.05)
14.22 (0.04) 13.86 (0.04)
C3 14.77 (0.05)
14.39 (0.05)
14.04 (0.05)
C4 15.49 (0.06)
15.14 (0.06)
14.81 (0.06)
C5 15.62 (0.06)
15.32 (0.05)
14.99 (0.06)
comparison stars from Fiorucci et al. 1998, PASP, 110, 105

Colour chart
Credit: SDSS  /  Size 13´× 13´ /  Chart by S. Karge

High resolution images of 1ES 0806+524

Credit: SDSS / Size 3´× 3´
This image from SDSS shows the host
galaxy of 1ES 0806+524 as a
starlike nucleus
surrounded by a
diffuse extended circular halo
(app. diam. 0.23´× 0.21´)
Credit: Scarpa et al. (1999) / Size 18.6"×18.6"
This image from Hubble Space Telescope
shows the well-resolved host galaxy.
(The arclike structure 1.9"
south of the bright
possibly is a bright elliptical shell or the
remnant of a previous gravitational interaction)

Light curve


1ES 0806+524 is a variable BL Lac object in north-eastern Lynx, close to the star 27 Lyn. The designation 1ES 0806+524 refers to the Einstein Slew Survey, where this object was cataloged as an X-ray source in the early 1990s. Initially, 1ES 0806+524 was discovered as a radio source in 1987 with the 91-m Green Bank radio telescope. Radio interferometry revealed a short northbound jet. The host galaxy of 1ES 0806+524 was identified as an elliptical galaxy with an apparent diameter of 0.23´× 0.21´. A remarkable arc-like structure, about 2" south of the nucleus, was found by the Hubble Space Telescope, which might be a bright elliptical shell or the remnant of a previous gravitational interaction. The first redshift of z=0.138 was measured in the late 1990s, based on weak absorption lines. Earlier attempts revealed only a featureless spectrum. Besides the radio and X-ray, 1ES 0806+524 was also identified as a gamma source by EGRET on board of Compton Gamma Ray Observatory in 1999/2000.

1ES 0806+524 is a small amplitude variable object with a total range of about 1.5 magnitudes. Depending on the actual brightness, visual observers need at least a 10- to 14-inch telescope or larger to glimpse this BL Lac object as a faint stellar object. With large instruments the object appears stellar or star-like. CCD observers, as well as visual observers, shall use the comparison stars given above.

1ES 0806+524 is located in north-eastern Lynx, only 50´N of the 4.8-mag star 27 Lyn. A nice observing object lies 7.5° NW, well suited for small telescopes. That is double star 19 Lyn (=STF1062), consisting of a 5.6-mag primary and a 6.5-mag companion (both type B stars), separated by 14.8".
nearby galaxies might also attract the observers interest. First turn the telescope 6.8° E to meet NGC 2681, a bright 11.1-mag face-on SB0a spiral, with a very bright stellar nucleus. Some 4° further to the east (11.3° E of 0806+524) there is NGC 2841, a large and bright 10.1-mag lense-shaped spiral.
A very special object is NGC 2685, 9.2° NE
in UMa, also dubbed the Helix- or Pancake-Galaxy. NGC 2685 is a 12.1-mag Polar-Ring Galaxy, the result of an ongoing galaxy merger (Arp 336), the brightest of its class.

Another bright extragalactic variable is waiting for the dedicated observer.
S5 0716+71 is a violently variable BL Lac object, located 19.7° N at a distance of about 3×109 light-years.
And finally, sweep the telescope 18.8° to the SSE to find another bright quasar. PG 0844+349 is a bright 13-mag to 14-mag object at a distance of about 0.8×109

Bade, N., Fink, H.H., Engels, D. 1994, A&A, 286, 381; New X-ray bright BL Lacertae objects from the ROSAT
     All-Sky Survey.
Becker, R.H., White, R.L., Edwards, A.L. 1991, ApJS, 75, 1B; A new catalog of 53,522 4.85 GHz sources.
Costamante, L., Ghisellini, G. 2002, A&A, 384, 56; TeV candidate BL Lac objects.
Fiorucci, M., Tosti, G., Rizzi, N. 1998, PASP, 110, 105; VRI Photometry of Stars in the fields of 16 Blazars.
Gioia, I.M., Maccacaro, T. 1990, ApJS, 72, 567; The Einstein Observatory Extended Medium-Sensitivity Survey.
     I - X-ray data and analysis.
Perlman, E.S., Stocke, J.T., et al. 1996, ApJS, 104, 251; The Einstein Slew Survey Sample of BL Lacertae Objects.
Rector, T.A., Gabuzda, D.C., Stocke, J.T. 2003, AJ, 125, 1060; The Radio Structure of High-Energy-Peaked
     BL Lacertae Objects.
Scarpa, R., Urry, C.M., et al. 1999, ApJ, 521, 134: Hubble Space Telescope Survey of BL Lacertae Objects:
     Gravitational lens Candidates and other unusual sources.
Schachter, J.F., Stocke, J.T., et al. 1993, ApJ, 412, 541; Ten new BL Lacertae objects discovered by an efficient
     X-ray/radio/optical technique.
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.


Landessternwarte Heidelberg

Sloan Digital Sky Survey

© Stefan Karge  /  last obs. 2023-1-12