Frankfurt Quasar Monitoring

PG 1700+518
Object data

  Cross-Identifications   SBS 1700+518, PG 1700+51, IRAS 17002+5153
  2MASS J17012482+5149204, QSO B1700+518
  1700+518, 2MASSi J1701248+514920
  Equat. coordinates   RA  17 01 25.0     DE  +51 49 20     (J2000)
  Constellation   Draco
  Type   QSO
  Redshift   z=0.292
  Distance (2) (3)
  1124 Mpc
  Total mag range (mv) (4) (5)   14.7 - 15.3
  Catalog Magnitude (1)   15.12
  Absolute Magnitude (1)   -25.8 MB
  Light Travel-Time (2)   3.226 × 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
1 14.231 (0.068)
13.655 (0.006)
2 14.847 (0.034)
14.261 (0.025)
3 15.139 (0.057) 14.612 (0.023)
4 15.987 (0.058) 15.163 (0.017)
16.902 (0.171) 15.946 (0.024)
comparison stars from APASS (DR6)

Colour chart
Credit: DSS2  /  Size 14´× 14´ /  Chart by S. Karge

Quasar PG 1700+518
This 20"× 20" H-band image from Hubble Space Telescope shows the bright point source of the
quasar and the highly disturbed neighbouring system, about 2" north of the quasar host.
Credit: Marquez et al. (2001)

Light curve

PG 1700+518 is a radio-quiet quasar in southern Draco, some 4° west of Draco´s head and close to the constellation Hercules. The designation PG 1700+518 refers to Palomar-Green Bright Quasar Survey (PG), where this object was discovered between 1976 and 1982 as a blue stellar object of magnitude B=15.43. Spectroscopic investigations revealed a Seyfert 1-spectrum with broad absorption lines. Therefore, PG:1700+518 was classified as a quasar (BAL quasar). As a blue stellar object, this quasar was also observed by both the Second Byurakan Survey (SBS) and the International Ultraviolet Explorer in the early 1980s. The most remarkable property of quasar PG 1700+518 is its strong emission in the infrared (IRAS, 2MASS). PG 1700+518 is considered as one of the infrared-brightest, radio-quiet quasars in the sky. High resolution images, taken by Hubble Space Telescope and ground based adaptive optics, revealed a galaxy collision between the host galaxy of PG 1700+518 and a highly disturbed neighbouring system, which most likely triggers the quasar activity of PG 1700+518 (see image above).

PG 1700+518 is a low amplitude variable object with a total range of only about 0.5 magnitudes in the optical. During Frankfurt Quasar Monitoring project, a variability of only about 0.2 magnitudes has been detected. This agrees well with the results from the Hamburg Quasar Monitoring programme.

CCD observers, as well as visual observers, shall use the comparison stars given above. Visual observers need at least a 10-inch telescope or larger to glimpse this quasar as a faint stellar object at a distance of about 3×109 light-years. Even with large instruments the quasar remains stellar. Locating quasar PG:1700+518 is quite easy: Just take the two brightest stars in the head of Draco, Gamma Draconis and Beta Draconis. Now, draw a line from Gamma to Beta. Move the same distance to the west and you are nearly there. A 7.85-mag field star, 10 arcmin NE of the quasar, leads directly to PG 1700+518 (see the bright star in the upper left corner of the finding chart above).

Two bright and interesting deep sky showpieces are worth visiting. The first is M92, a bright globular cluster about 9° to the SSE. M92 is some 30 000 light-years distant and can be resolved using an 8-inch telescope or larger. Another globular cluster, NGC 6229, can be found 4.8° to the SSW. NGC 6229 is considered to be about 100:000 light-years away. The brightest stars in NGC 6229 are of mag 15.5, so observers need at least 12- to 14-inch of aperture to resolve some few very faint stars of NGC 6229.

Finally, observers may like to turn to quasar PG 1718+481, a bright 14-mag object at the remarkable distance of nearly 8×109 light-years (!), only 4.7° SE.

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     Byurakan Survey (SBS) with the Digitized Sky Survey.
Boroson, T.A., Green, R.F. 1992, ApJS, 80, 109; The Emission-Line Properties of Low-Redshift Quasi-Stellar Objects.
Chavushyan, V.O., Stepanian, J.A., et al. 1995, AstL, 21, 804; CCD Photometry of QSO's from the Second Byurakan
Giveon, U., Maoz, D., et al. 1999, MNRAS, 306, 637G; Long-term Optical Variability Properties of the Palomar-Green
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Hutchings, J.B., Neff, S.G. 1992, AJ, 104, 1; Optical Imaging of QSOs with 0.5 arcsec Resolution.
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Karge, S.; Helle Quasare für 8- bis 10-Zoll Teleskope. Ein Beobachtungsführer zur visuellen Beobachtung von Quasaren
     und BL Lacertae Objekten; Frankfurt 2005.
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Márquez, I., Petitjean, P., et al. 2001, A&A, 371,97; Adaptive Optics Imaging of Low and Intermediate Redshift Quasars.
Pettini, M., Boksenberg, A. 1985, ApJ, 294, 73; PG 1700+518 - A Low-Redshift, Broad Absorption Line QSO.
Richards, G.T., Yanny, B., et al. 1997, PASP, 109, 39R; Quasar Photometry with the SDSS Monitor Telescope.
Schmidt, G.D., Hines, D.C. 1999, ApJ, 512, 125; The Polarization of Broad Absorption Line QSOs.
Schmidt, M., Green, R. 1983, ApJ, 269, 352; Quasar Evolution Derived from the Palomar Bright Quasar Survey and Other
     Complete Quasar Survey.
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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.


Hamburg Quasar Monitoring


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