Frankfurt Quasar Monitoring

RX J1230.8+0115
Object data

  Cross-Identifications   QSO B1228+0131, SDSS J123050.03+011522.6
  QSO J1230+0115, 2MASS J12305003+0115226
  HE 1228+0131, 1RXS J123050.4+011526
  GALEXASC J123050.07+011522.5

  Equat. coordinates   RA  12 30 50.0      DE  +01 15 21     (J2000)
  Constellation   Virgo
  Type   QSO
  Redshift   z=0.117
  Distance (2) (3)   473 Mpc
  Total mag range (mv) (4) (5)   14.4 - 14.8
  Catalog Magnitude (1)   14.42
  Absolute Magnitude (1)   -24.8 MB
  Light Travel-Time (2)   1.460 × 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
B 14.411 (0.055)
13.803 (0.038)
C 14.803 (0.052)
14.066 (0.059)
D 14.756 (0.046) 14.266 (0.033)
E 14.928 (0.075) 14.751 (0.020)
F 15.661 (0.051) 15.069 (0.016)
16.124 (0.082) 15.754 (0.144)
comparison stars from APASS (DR6)

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

Light curve

RX J1230.8+0115 is a bright radio-quiet quasar in Virgo, 3.3° NE of Eta Vir, and only about 1° SE of famous quasar 3C 273. At a distance of about 1.4×109 light-years, RX J1230.8+0115 is located in the far cosmological background of the southern extension of the Virgo galaxy cluster.
In the early 1990s, quasar RX J1230.8+0115 was discovered as an X-ray source by ROSAT. During follow-up observations, carried out by the Edinburgh UVX Quasar Survey, the new source was identified with a stellar object that showed a Seyfert 1-spectrum. At the time of discovery, this newly found quasar was # 9 among the brightest quasars in the sky. It remains unclear why this bright quasar was not detected by the Palomar-Green Survey (1976-1992). The PG-Survey was the only survey that previously scanned this area of the sky searching for blue stellar objects as potential quasar candidates. Probably, quasar RX J1230.8+0115 underwent larger flux changes in the past.

RX J1230.8+0115
is a low amplitude variable object. According to the Frankfurt Quasar Monitoring programme, the total optical variability ranges only within a few tenth of a magnitude. CCD observers, as well as visual observers, shall use the comparison stars given above. For visual observers with apertures of 10- to 12-inch and larger, this quasar appears as a stellar object - even with large aperture telescopes.

Right next to
the quasar there is a nice triple star, WDS 12312+0120, only 7´NE (see finding chart above, labelled as WDS). The 7
.7-mag primary and the 8.7-mag secondary are separated by 49". The third component is a 10.5-mag star, only 5" N of the secondary.
The star field NE of quasar RX J1230.8+0115 shows two bright 11-mag spirals, about 1.4° to the NE: NGC 4536 and NGC 4527. Both galaxies are type SBbc-spirals and members of the Virgo galaxy cluster.

As mentioned above, another quasi-stellar object, famous quasar "superstar" 3C 273 can be found only 1° NW and is a must for all observers. Due to the proximity to 3C 273, the author calls QSO
RX J1230.8+0115 "the fainter little brother of 3C 273". So when you are around for quasar RX J1230.8+0115, why not taking a look at 3C 273 as well ?
Another violently variable quasar,
3C 279, can be found by moving the scope some 9° to the SE. 3C 279 is located at a whopping distance of some
5×109 light-years.

Goldschmidt, P., Miller, L. 1998, MNRAS, 293, 107; The UVX quasar optical luminosity function and its evolution.
Karge, S.; Helle Quasare für 8- bis 10-Zoll Teleskope. Ein Beobachtungsführer zur visuellen Beobachtung von
     Quasaren und BL Lacertae Objekten; Frankfurt 2005.
Read, M.A., Miller, L., Hasinger, G. 1998, A&A, 335, 121; A bright QSO near 3C273.
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.


Sloan Digital Sky Survey


© Stefan Karge  /  last obs. 2022-12-11