Frankfurt Quasar Monitoring

OQ 530
Object data

  Cross-Identifications   OQ+530, PG 1418+546, S4 1418+54, CSO 633
  TXS 1418+546, GB6 J1419+5423, GC 1418+54
  2E 1418.1+5436, SDSS J141946.60+542314.8
  87GB 141807.0+543717, WMAP J1419+5425
  SBS 1418+546, RGB J1419+543, 1418+546
  CXO J141946.6+542314, QSO B1418+54
  IRAS F14180+5437, RX J1419.7+5423
  GALEXASC J141946.61+542315.9

  Equat. coordinates   RA  14 19 46.6     DE  +54 23 14     (J2000)
  Constellation   Bootes
  Type   BL Lac
  Redshift   z=0.152
  Distance (2) (3)
  608 Mpc
  Total mag range (mv) (4)   10.8 - 16.5
  Catalog Magnitude (1)   15.65
  Absolute Magnitude (1)   -23.7 MB
  Light Travel-Time (2)   1.847 × 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 V B-V U-B
A 9.27 0.55 0.05
B 12.81 0.88 0.56
C 14.29 0.62 0.13
D 13.66 0.55 -0.03
E 15.89 0.80: 1.14:
G 14.94 0.53 -0.02
comparison stars from Miller et al. 1984, A&AS, 57, 353

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

High resolution images of OQ 530
Credit: SDSS / Size 3´× 3´
This image shows the host galaxy of
OQ 530 with a
bright star-like nucleus

(apparent diameter 15"×10")
Credit: Nilsson et al. (2003) / Size 44.2" × 44.2"
This R-band image by the Nordic Optical
Telescope shows the host galaxy
as an
elongated disk galaxy
(image inverted)

Light curve

OQ 530 = 1418+546 is a violently variable BL Lac object in north-eastern Bootes, very close to the constellation Ursa Major. The designation OQ 530 refers to the radio survey of the Ohio State University (OQ) where this object was discovered as a radio source. Soon after the discovery, this radio source was identified with a star-like object by the Case University Survey (CSO). OQ 530 is a radio loud object, and as such, it has been catalogued by various other radio surveys. Radio interferometry revealed a radio jet extending to the southeast. The high resolution images above clearly show this BL Lac object at the centre of an elongated disk galaxy. The surface brightness profile resembles that of an S0-type galaxy, although some authors found evidence to classify this galaxy as a flattened elliptical.

Blazar OQ 530 is both a highly polarized and a violently variable object. The total optical range was found to be nearly 6 magnitudes in the optical! Intraday optical variability has been recorded as well.
CCD observers, as well as visual observers, shall use the comparison stars given above.
Other photometric sequences were published by Smith et al. (1985) and the Perugia Blazar List. Visual observers need at least a 14-inch telescope or larger to glimpse this stellar object. Visually, no hints of the host galaxy can be found even with very large aperture telescopes.

Let´s have a look at some interesting observing targets near OQ 530. Observers who like to focus on some more very old quasi-stellar photons may turn to a bright 14-mag quasar, located some 10° to the north: PG:1351+64 is a low amplitude variable object at a distance of 1.1×109 light-years.
CCD observers may recognize another faint quasi stellar object in their CCD frames: SBS 1418+548, an 18-mag high redshift quasar, denoted as "Q" at the upper edge of the finding chart. Quasar SBS 1418+548 has a redshift of z=2.257, which corresponds to a light travel-time of about 10×109 yrs (see further data below).

Galaxy fans find three deep sky showpieces nearby. M101, a large face-on spiral, can be found some 2.4° to the east. Pointing the telescope 10.5° to the SE of OQ 530 shows M51, the "Whirlpool galaxy", as well as its bright companion, NGC 5195. Finally turn 6.8° to the west of OQ 530 and visit M102 (NGC 5866), a bright 10.8-mag edge-on galaxy, with a narrow dust lane intersecting the bright bulge.

Back in our Milky Way galaxy, we close our deep sky session with a look at a pair of bright and easy double stars, separated in the sky by only half a degree. Kappa (17) Bootis is located some 2.7° SSE of OQ 530. It consists of a 4.5-
mag primary and a 6.6-mag companion, separated by 13.7". Nearby double star Iota (21) Bootis is located just 35 arcmin SE. It has a 4.9-mag primary and a 7.5-mag companion, separated by 40".

[SBS 1418+548 = SDSS J141954.26+543014.8:  RA 14 19 54.1,  DE +54 30 15,  z=2.257,  18.28 mag]*
*Data from Véron-Cetty & Véron (2006)

Fan, J.H., Lin, R.G. 1999, ApJS, 121, 131; Infrared Variation of Radio-selected BL Lacertae Objects.
Gabuzda, D.C., Pushkarev, A.B., Cawthorne, T.V. 1999, MNRAS, 307, 725; The lambda=6cm VLBI polarization structure
     of nine BL Lacertae objects.
Miller, H.R., Wilson, J.W., et al. 1984, A&AS, 57, 353; Photoelectric comparison sequences in the fields of B2 1308+326
     and 1418+54.
Nilsson, K., Pursimo, T., et al. 2003, A&A, 400, 95; R-band imaging of the host galaxies of RGB BL Lacertae objects.
Smith, P.S., Balonek, T.J., et al. 1985, AJ, 90, 1184; UBVRI Field Comparison Stars for Selected Aktive Quasars and BL
     Lacertae Objects.
Steinicke, W.; Katalog heller Quasare und BL Lacertae Objekte; Umkirch 1998.
Stickel, M., Fried, J.W., Kuehr, H. 1993, A&AS, 98, 393; The complete sample of 1 Jy BL Lac objects. II - Observational
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.

© Stefan Karge  /  last obs. 2020-01-15