Frankfurt Quasar Monitoring

4C 29.45
Object data

  Cross-Identifications   TON 599, 4C +29.45, OM+295, CTD 77, CSO 166
  PKS 1156+295, FBQS J1159+2914, 1156+295
  2MASSi J1159317+291443, 2EG J1158+2906
  LEDA 2820106, B2 1156+29, TXS 1156+295
  87GB 115657.7+293133, RX J1159.5+2914
  SDSS J115931.83+291443.8 
  Equat. coordinates   RA  11 59 31.9     DE  +29 14 45     (J2000)
  Constellation   Ursa Major
  Type   QSO
  Redshift (2)   z=0.724
  Distance (2) (3)   2510 Mpc
  Total mag range (mv) (4) (5)   12.8 - 18.5
  Catalog Magnitude (1)   14.41
  Absolute Magnitude (1)   -28.6 MB
  Light Travel-Time (2)   6.260 × 109 yrs
(1) Véron-Cetty & Véron 2006, A&A 455, 776
(2) NASA/IPAC Extragalactic Database
(3) Co-Moving Radial Distance
(4) Frankfurt Quasar Monitoring
(5) Literature

Finding chart


Comparison stars

star B V Rc
1 14.01 (0.06)
13.39 (0.05)
13.01 (0.02)
2 16.01 (0.06)
15.38 (0.05)
15.00 (0.02)
3 16.44 (0.04)
15.91 (0.04)
15.54 (0.02)
4 17.15 (0.05)
16.60 (0.04)
16.28 (0.02)
comparison stars from Raiteri et al. 1998, A&AS, 130, 495

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

Light curve


4C 29.45 is a violently variable quasar in southern Ursa Major, close to the constellations Coma Berenices and Leo. 4C 29.45 was discovered as a "blue stellar object" in the late 1950s by mexican Tonantzintla Blue Stellar Objects Survey (TON). In the 1960s, this blue stellar object was identified as the optical counterpart of the radio source 4C 29.45, which was detected by the 4th Cambridge Radio Survey (4C). Since then, 4C:29.45 has been cataloged by several other radio surveys. In addition, it was detected as a source of both X-ray and gamma emissions.

4C 29.45 displays extremely large and rapid flux variations at both radio and optical wavelengths, with variability time-scales varying from minutes to years - a typical OVV. 4C 29.45 is optically very active with a total range of nearly 6 magnitudes, showing large optical outbursts.
Observations by the Frankfurt Quasar Monitoring programme have recorded minimum magnitudes down to about 18.5 mag. This is 0.4 magnitudes fainter than the data from the literature.

Visual observers with telescopes of 8- to 10-inch of aperture may only observe this quasar during times of outburst. Large aperture telescopes improve the chance of catching this quasar in the eyepiece. 4C 29.45 is most suitable for CCD observers, as this quasar displays brightness variations from day to day. Due to its large distance of more than 6×109 light-years this quasar only shows up as a stellar object.
CCD observers, as well as visual observers, shall use the comparison stars given above. Other photometric sequences were published by Wills et al. (1983), Smith et al. (1985), Gonzŕlez-Pérez et al. (2001), and the AAVSO.

Starting our visual trip into the vicinity of
4C 29.45 we first move about 6° to the SE, where we take a look at the large naked eye open cluster Mel 111, also dubbed the "Coma Cluster", only about 280 light-years away. Turning 4.5° to the E we find the neighbouring galaxy group around NGC 4274.

Another bright extragalactic variable, W Com, is located some 5° E of quasar 4C 29.45. And finally, a variable quasar, GQ Com (=PG 1202+282), is situated 1.7° SE of 4C 29.45.

Aldcroft, T.L, Bechtold, J., Elvis, M. 1994, ApJS, 93, 1; MgII Absorption in a Sample of 56 Steep-Spectrum Quasars.
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     from November 1994 to November 1995.
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Wills, D. 1966, The Observatory 86, 245; 4C Radio Sources and Blue Stellar Objects.


Landessternwarte Heidelberg (1)

Landessternwarte Heidelberg (2)


Hamburg Quasar Monitoring

Sloan Digital Sky Survey


VSNET Alert 27321: Optical Flare of Quasar Ton 599 (4C +29.45)

© Stefan Karge (FQM)  /  last obs. 2024-05-05