Frankfurt Quasar Monitoring

MRK 478
Object data

  Cross-Identifications   PG 1440+356, IRAS 14400+3539, PGC 52510
  2MASSi J1442074+352622, EUVE J1442+35.4
  FIRST J144207.4+352623, RX J1442.1+3526
  1AXG J144207+3526, 2XMM J144207.4+352622 
  GALEXASC J144207.57+352623.7, 1440+356
  SDSS J144207.47+352622.9, 1H 1429+370
  Markarian 478
  Equat. coordinates   RA  14 42 07.5     DE  +35 26 23     (J2000)
  Constellation   Bootes
  Type   QSO
  Redshift (2)   z=0.079
  Distance (2) (3)
  321 Mpc
  Total mag range (mv) (4)   14.3 - 14.8
  Catalog Magnitude (1)   14.58
  Absolute Magnitude (1)   -23.4 MB
  Light Travel-Time (2)   1.009 × 109 yrs
(1) Véron-Cetty & Véron 2006, A&A 455, 776
(2) NASA/IPAC Extragalactic Database
(3) Co-Moving Radial Distance
(4) Literature / FQM

Finding chart

Comparison stars

star B V
A 14.457 (0.063)
13.840 (0.061)
B 14.846 (0.073)
14.139 (0.066)
C 15.252 (0.048)
14.612 (0.066)
D 15.736 (0.193) 15.159 (0.118)
comparison stars from APASS (DR6)

Light curve

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

Colour chart B
This 3´× 3´section from SDSS shows the quasar host of MRK 478 as a slightly
oval galaxy disk (apparent diameter 30"×20") with a bright stellar core.
Credit: SDSS  /  Size 3´× 3´

Markarian 478 (MRK 478 for short) is a bright quasar in Bootes, about 3.5° SE of Gamma Bootis. MRK 478 was discovered in 1972 by the UV-Continuum-Survey run by Markarian et al. (MRK) at the Astrophysical Observatory in Byurakan/Armenia. Main goal was the spectroscopic search for "blue" galaxies with excessive UV-emission. MRK 478 was detected as a very compact, star-like object. As a blue star-like object it was also detected by both the Palomar-Green Bright Quasar Survey (PG) and the Extreme Ultraviolet Explorer (EUVE). The quasar host is a spiral galaxy with an apparent diameter of 30"×20". The host itself shows clear signs of disturbance, detectible as faint shells or arms. The very bright nucleus emits a Narrow-Line Seyfert 1-spectrum (NLS1), very similar to that found with I Zw 1.

MRK 478 is a low amplitude variable object with a total range of less than 1 magnitude. Visual observers need at least an 8- to 10-inch telescope to glimpse this stellar object. Using large aperture telescopes, the quasar becomes either star-like or a star-like object, enveloped by a very diffuse and small halo. With very large aperture and high power, observers may recognize a slightly bluish hue of the bright star-like nucleus, a result of the UV-excess of this active galactic nucleus.
CCD observers, as well as visual observers, shall use the comparison stars given above.

Finding MRK 478 is an easy task due to its position 3.5° SE of Gamma Bootis. A little south of Gamma Bootis, a chain of stars of mag 6 and mag 7 directly point to the quasar. Only 1.5° NE, we find the faint galaxy NGC 5695, also known as MRK 686, an active galaxy with S2-spectrum. As with MRK 478, this AGN was also found by the UV-Continuum-Survey mentioned above.

Observers who like to track down some more very old quasi-stellar photons may turn to quasar PG 1411+442, a bright 14-mag object at a distance of about 1×109 light-years, some 10° NW of MRK 478.
Another bright
quasi-stellar object is PKS 1424+240, a variable 14-mag BL Lac object, located about 12° SSW of MRK 478.

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     the Point Source Catalogue (PSC).
Gondhalekar, P.M., Kellett, B.J., et al. 1994, MNRAS, 268, 973; ROSAT/XRT-PSPC Observations and the Ionizing
     Continuum of the Seyfert 1 Galaxy Mrk 478.
Hansen, T. 1991, Deep Sky Magazine 34, 32; The "Deepest" Deep Sky Objects.
Karge, S.; Helle Quasare für 8- bis 10-Zoll Teleskope. Ein Beobachtungsführer zur visuellen Beobachtung von Quasaren
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Schmidt, M., Green, R.F. 1983, ApJ, 269, 352; Quasar Evolution derived from the Palomar Bright Quasar Survey and
     other complete Quasar Surveys.
Steinicke, W.; Katalog heller Quasare und BL Lacertae Objekte; Umkirch 1998.
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Véron-Cetty, M.-P., Véron, P. 2003, A&A 412, 399; A Catalogue of Quasars and Active Nuclei: 11th edition.
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Webb, W., Malkan, M. 2000, ApJS, 130, 165; Comparison star sequences for optical photometry of Active Galactic
     Nuclei and Quasars.





Sloan Digital Sky Survey

© Stefan Karge  /  last obs. 2022-12-21