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NRAO 140

NRAO 140
The quasar NRAO 140.
Observation data (J2000.0 epoch)
ConstellationPerseus
Right ascension03h 36m 30.1076s
Declination+32° 18′ 29.342″
Redshift1.265200
Heliocentric radial velocity379,297 km/s
Distance8.432 Gly
Apparent magnitude (V)17.50
Characteristics
TypeOpt. var, LPQ, RLQ
Other designations
INTREF 154, LEDA 2820229, QSO J0336+3218, OHIO E 355, 2E 801, 1H 0332+317, 4C 32.14, DA 107, RX J0336.5+3218

NRAO 140 is a quasar[1] located in the constellation of Perseus, noted for its low frequency variability.[2] It has a redshift of (z) 1.258,[3][4] first discovered in 1973 by Duncan Agnew and Halton Arp as an astronomical radio source, whom they catalogued it as 4C 32.14.[5]

Description

NRAO 140 is classified as a radio-selected blazar (RBL) based on European X-ray Observatory Satellite (EXOSAT) observations. However the object has no presence of either long-term or rapid fluxes. Its radio spectrum is flat, making it a flat-spectrum source,[6] but also exhibiting radio and X-ray fluxes that lasted between 1979 and 1985.[7] The brightness temperature of NRAO 140 is estimated to be between 5 x 1015 and 5 x 1014 Kelvin.[8]

A low frequency outburst was detected in NRAO 140 by the Very Long Baseline Array (VLBI) observations, peaking in 1981 with the component undergoing a decrease in brightness levels as the outburst faded.[9][10] Between August 7 and 9 in 1986, the object displayed rising levels in K flux from 1.25 ± 0.06 mJy to around 1.54 ± 0.05 mJy in a span of two days during the observation campaign.[1]

Radio imaging made by Very Large Array (VLA) at both 21 and 6 centimeters (cm) shows the structure of NRAO 140 is made up of only a single secondary component with a position angle of 150°. Other radio images made by the Westerbork Synthesis Radio Telescope shows NRAO 140 has two components located on both sides of the radio core, consisting of a southwestern component at a position angle of 149° and a northeastern component at a position angle of -31° opposed to images made by VLA.[11] VLBI observations also shows evidence of superluminal motion in several components separating at an angular rate of 0.10-0.14 milliarcseconds.[12]

The jet in NRAO 140 is found to bend slightly towards the south direction from the radio core with detections of polarized flux in its jet components. In additional, the position angle of the jet is found nearly perpendicular towards the jet's axis, with the jet itself having a faraday rotation measure gradient extended by 8 milliarcseconds from the core. By constraining the upper limits of the jet's viewing angle, the jet is confirmed to have a linear extent greater than 350 parsecs.[13]

References

  1. ^ a b Courvoisier, T.J.; Bell-Burnell, J.; Blecha, A. (1986). "Optical and infrared study of the three quasars OX 169, NRAO 140 and 3C 446". Astronomy & Astrophysics. 169 (1–2): 43–48. Bibcode:1986A&A...169...43C. ISSN 0004-6361.
  2. ^ Fey, Alan L.; Clegg, Andrew W.; Fiedler, Ralph L. (September 1996). "VLBI Observations of Eight Extreme Scattering Event Sources: Milliarcsecond-Scale Structure". The Astrophysical Journal. 468: 543. Bibcode:1996ApJ...468..543F. doi:10.1086/177713. ISSN 0004-637X.
  3. ^ Maisack, M.; Staubert, R.; Otterbein, K.; Witzel, A.; Wagner, S.J.; Heines, A. (1996). "CGRO, radio and optical observations of the quasar NRAO 140". Astronomy and Astrophysics Supplement Series. 120: 533–536. Bibcode:1996A&AS..120C.533M.
  4. ^ Marscher, Alan P.; Broderick, John J. (1982), Heeschen, David S.; Wade, Campbell M. (eds.), "Superluminal Motion in NRAO 140 and a Possible Future Method for Constraining Ho and qo", Extragalactic Radio Sources, Dordrecht: Springer Netherlands, pp. 359–360, doi:10.1007/978-94-009-7781-5_99, ISBN 978-94-009-7781-5, retrieved 2024-12-28
  5. ^ Agnew, Duncan; Arp, Halton (April 1973). "A List of Quasi-Stellar Radio Sources and Quasi-Stellar Radio Source Candidates from the 3C and 4C Catalogs Between Declination -7° and +40°". Publications of the Astronomical Society of the Pacific. 85: 162. Bibcode:1973PASP...85..162A. doi:10.1086/129427. ISSN 0004-6280.
  6. ^ Mufakharov, T.; Mingaliev, M.; Sotnikova, Yu.; Naiden, Ya.; Erkenov, A. (2015-05-07). "The observed radio/gamma-ray emission correlation for blazars with the Fermi-LAT and the RATAN-600 data". Monthly Notices of the Royal Astronomical Society. 450 (3): 2658–2669. doi:10.1093/mnras/stv772. ISSN 0035-8711.
  7. ^ Ghosh, K.K.; Soundararajaperumal, S. (1995). "Multifrequency Spectra of EXOSAT Blazars". The Astrophysical Supplement Series. 100: 37–68. Bibcode:1995ApJS..100...37G. doi:10.1086/192207.
  8. ^ Marscher, A. P.; Broderick, J. J. (March 1985). "Multifrequency radio VLBI observations of the superluminal low-frequency variable quasar NRAO 140". The Astrophysical Journal. 290: 735. doi:10.1086/163031. ISSN 0004-637X.
  9. ^ P. Marsche, Alan; J. Broderick, John; Padrielli, Lucia; Bartel, Norbert; D. Romney, Jonathan (1987). "18 CENTIMETER VLBI OBSERVATIONS OF THE QUASAR NRAO 140 DURING AND AFTER A LOW-FREQUENCY OUTBURST". The Astrophysical Journal. 319: 456–464. doi:10.1086/165470.
  10. ^ Marscher, A.P. (1987). "5 years of VLBI and X-ray observations of NRAO 140". The Impact of VLBI on Astrophysics and Geophysics; Proceedings of the 129th IAU Symposium, Cambridge, MA, May 10-15, 1987: 35–36. Bibcode:1988IAUS..129...35M.
  11. ^ Altschuler, D.R.; Gurvits, L.I.; Alef, W.; Dennison, B.; Graham, D.; Trotter, A.S. (1995). "The centi-arcsecond structure of 16 low-frequency variable sources at 92 cm". Astronomy and Astrophysics Supplement Series. 114: 197–114. Bibcode:1995A&AS..114..197A.
  12. ^ Marscher, A. P.; Broderick, J. J. (April 1982). "Apparent superluminal motion in the quasar NRAO 140". The Astrophysical Journal. 255: L11. doi:10.1086/183760. ISSN 0004-637X.
  13. ^ Asada, Keiichi; Inoue, Makoto; Nakamura, Masanori; Kameno, Seiji; Nagai, Hiroshi (August 2008). "Multifrequency Polarimetry of the NRAO 140 Jet: Possible Detection of a Helical Magnetic Field and Constraints on Its Pitch Angle". The Astrophysical Journal. 682 (2): 798–802. doi:10.1086/588573. ISSN 0004-637X.
Quelle: http://en.wikipedia.org/wiki/NRAO_140