Frankfurt Quasar Monitoring


MG 0509+0541
Object data

  Cross-Identifications   MG J0509+0541, TXS 0506+056, ZS 0506+056
  QSO B0506+056, RX J0509.3+0541, 0506+056
  2MASS J05092597+0541353, GB6 J0509+0541
  87GB 050645.2+053747, 1FGL J0509.3+0540
  EGR J0509+0550, 1RXS J050927.0+054145
  CGRaBS J0509+0541, MG1 J050927+0541
  WISE J050925.96+054135.3
  Equat. coordinates   RA  05 09 25.9     DE  +05 41 35     (J2000)     
  Constellation   Orion
  Type   BL Lac
  Redshift (2)   z=0.3365
  Distance (3) (4)
  ~1750 Mpc
  Total mag range (mv) (5)   14.23 - 16.1
  Catalog Magnitude (1)   16.00
  Absolute Magnitude (1)   --- MB
  Light Travel-Time (6)   3.78 × 109 yrs
(1) Véron-Cetty & Véron 2006, A&A 455, 776
(2) Paiano, S., et al. (2018)
(3) Luminosity Distance
(4)
Keivani, A., et al. (2018)
(5) FQM / CRTS
(6) NASA/IPAC Extragalactic Database

Finding chart
0506+056_chart_fqm.jpg

Comparison stars

star B V
1 15.143 (0.041) 14.495 (0.037)
2 15.273 (0.083)
14.649 (0.049)
3 15.337 (0.036)
14.926 (0.051)
4 15.583 (0.023) 15.032 (0.055)
5 15.692 (0.023) 15.241 (0.050)
6
16.050 (0.114) 15.364 (0.035)
7
16.227 (0.095) 15.824 (0.056)
comparison stars from APASS (DR6)

Colour chart
0506+056_color_fqm.jpg
Credit: DSS2  /  Size 14´x 14´ /  Chart by S. Karge
Light curve
0506+056_lc1901_fqm.jpg

Notes
MG 0509+0541 = TXS 0506+056 is a variable BL Lac object in Orion, roughly 4° W of Bellatrix (Gamma Ori). The designation MG 0509+0541 refers to the MIT-Green Bank 5 GHz Survey (MG), where this object was detected as a radio source in 1981-82. Today, MG 0509+0541 is classified as a BL Lac object due to its (nearly) featureless spectrum. It took until 2018 when the first redshift could be determined based on very weak emission lines, detected with the 10.4m Gran Telescopio Canarias.

MG 0509+0541 attracted attention in September 2017, when a high-energy neutrino was detected
by IceCube, designated IceCube-170922A. The arrival direction of this 290 TeV neutrino was
consistent with the location of gamma-ray blazar MG 0509+0541 = TXS 0506+056, observed to be
in a flaring state (see light curve above) with enhanced gamma-ray activity in the GeV range.


As for most BL Lac objects, this source was found to be rapidly variable in the optical by up to 2 magnitudes, ranging between 14.2 - 16.1 mag. During bright state, visual observers may observe this blazar with telescopes of 8- to 10-inch of aperture. The object appears stellar even with large apertures.
CCD observers, as well as visual observers, shall use the comparison stars given above.

____________

MG 0509+0541 is located in eastern Orion, only about 4° W of Bellatrix (Gamma Ori). The constellation Orion is well known for its spectacular nebula landscapes, like the Great Orion Nebula M42/43 (12° SE), the Horse Head Nebula B33/IC 434 (11° SE) and the Flame Nebula NGC 2024 (11° SE), just to mention the most popular ones.

A more challenging deep sky object is another quasar, PKS 0405-12, a bright 14-mag stellar object at a distance of more than 5×109 light-years, located some 23° SW in Eridanus.



Literature
Amirkhanyan, V.R., Gorshkov, A.G., et al. 1992, SvA, 36, 115; Complete Sample of Radio Sources at 3.9, 4.8,
     7.5, and 11.2 GHz from the Zelenchuk Survey.
Beasley, A.J., Gordon, D., et al. 2002, ApJS, 141, 13; The VLBA Calibrator Survey - VCS1.
Chavushyan, V., Mujica, R., et al. 2001, Arep, 45, 79; Radio and Optical Spectra of Objects from Two Complete
     Samples of Radio Sources.
Halpern, J.P., Eracleous, M., Mattox, J.R. 2003, AJ, 125, 572; Redshifts of Candidate Gamma-Ray Blazars.
Karge, S.; Helle Quasare für 8- bis 10-Zoll Teleskope. Ein Beobachtungsführer zur visuellen Beobachtung von
     Quasaren und BL Lacertae Objekten; Frankfurt 2005.
Keivani, A., et al. 2018, ApJ 864, 84; A Multimessenger Picture of the Flaring Blazar TXS 0506+056: Implications
     for High-energy Neutrino Emission and Cosmic-Ray Acceleration.
Lawrence, C.R., Bennett, C.L., et al. 1986, ApJS, 61, 105; 5 GHz Radio Structure and Optical Identifications of
     Sources from the MG Survey. II - Maps and Finding Charts.
Paiano, S., et al. 2018, ApJ 854L, 32P; The Redshift of the BL Lac Object TXS 0506+056.
The IceCube Collaboration et al. 2018, Science 361, eeat1378; Multimessenger Observations of a Flaring Blazar
    Coincident with High-Energy Neutrino IceCube-170922A.
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.



© 2019-01-03 by Stefan Karge






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