4C 39.25

Last updated
4C 39.25
4C 39.25 Pan-STARRS i.r.g.jpg
The quasar 4C 39.25
Observation data (J2000.0 epoch)
Constellation Leo Minor
Right ascension 09h 27m 03.0139s
Declination +39° 02′ 20.850″
Redshift 0.695898
Heliocentric radial velocity 208,625 km/s
Distance 6.102 Gly
Apparent magnitude  (V)17.00
Characteristics
Type Opt. var.; Sy1, LPQ
Other designations
DA 267, QSO B0923+392, LEDA 2820605, RBS 776, 7C 092355.20+391523.00

4C 39.25 is a quasar located in the constellation of Leo Minor with a redshift of (z) 0.698. [1] It was first discovered in 1966 as an astronomical radio source and subsequently identified with a blue stellar object in 1967. [2] [3] The object is known to have a superluminal jet. [4] [5]

Contents

Description

4C 39.25 is classified as a high frequency peaker (HFP). [6] It is shown to display strong flux density variations although not highly variable. [6] [7] Its radio spectrum is found to have a convex shape with a peak of 11 GHz. Additionally, the object also has significant variability, detected at all frequencies. [6] Between 1996 and 2003, the flux density of the source at 3 millimetre dropped from 6 to 3 Jansky (Jy). However it rose again to present flux density levels of 4.5 Jy. [8]

The source of 4C 39.25 is compact. [9] [10] Its radio structure is best described as a simple double source but also contracting, containing a most compact feature on the western region. [11] [12] Radio imaging observations on sub-arcsecond scale showed the source as core-dominated, containing a bright radio core surrounded by radio emission. [13] The core is found elongated in all directions according to observations by Very Long Baseline Interferometry (VLBI). [14] Very Large Array (VLA) radio mapping on arcseconds depicted the structure of the source as symmetric, resolved by shorter wavelengths as a lumpy jet embedded in an emission region. [15]

4C 39.25 contains a bend jet which extends eastwards. [15] [5] The jet is shown to have an emission bridge linking from one component to another. [16] Within the jet, lies two individual stationary components located in west and east directions. In the middle of the components, there is another component moving by about 0.16 or −0.02 microarcsecond each year, in agreement to an average speed measuring between 3.2c and 8.4c, confirming superluminal motion. [17] Evidence also showed the source has a strong discrepancy in its X-ray flux density, with its relativistic motion mainly originating from excessive inverse Compton flux. [18]

References

  1. ↑ Fey, Alan L.; Eubanks, Marshall; Kingham, Kerry A. (December 1997). "The Proper Motion of 4C 39.25". The Astronomical Journal. 114: 2284. Bibcode:1997AJ....114.2284F. doi:10.1086/118648. ISSN   0004-6256.
  2. ↑ Long, R. J.; Smith, M. A.; Stewart, P.; Williams, P. J. S. (1966-12-01). "The Radio Spectra of Sources in the Fourth Cambridge Catalogue". Monthly Notices of the Royal Astronomical Society. 134 (4): 371–388. doi: 10.1093/mnras/134.4.371 . ISSN   0035-8711.
  3. ↑ Wills, D. (1967-01-01). "Optical identifications of selected 4C radio sources". Monthly Notices of the Royal Astronomical Society. 135: 339. doi: 10.1093/mnras/135.4.339 (inactive 1 July 2025). ISSN   0035-8711.{{cite journal}}: CS1 maint: DOI inactive as of July 2025 (link)
  4. ↑ Marscher, Alan P.; Schaffer, David B.; Booth, Roy S.; Geldzahler, Barry J. (1987-08-01). "Multifrequency VLBI Observations of 4C 39.25: A Superluminal Source without a Well-defined Core". The Astrophysical Journal. 319: L69. Bibcode:1987ApJ...319L..69M. doi:10.1086/184956. ISSN   0004-637X.
  5. 1 2 Alberdi, A.; Marcaide, J. M.; Marscher, A. P.; Zhang, Y. F.; Elosegui, P.; Gomez, J. L.; Shaffer, D. B. (1993-01-01). "The Parsec-Scale Radio Jet of 4C 39.25". The Astrophysical Journal. 402: 160. Bibcode:1993ApJ...402..160A. doi:10.1086/172119. ISSN   0004-637X.
  6. 1 2 3 Torniainen, I.; Tornikoski, M.; Teräsranta, H.; Aller, M. F.; Aller, H. D. (2005-05-13). "Long term variability of gigahertz-peaked spectrum sources and candidates" (PDF). Astronomy & Astrophysics. 435 (3): 839–856. Bibcode:2005A&A...435..839T. doi:10.1051/0004-6361:20041886. ISSN   0004-6361.
  7. ↑ Pearson, T. J.; Readhead, A. C. S. (May 1988). "The milliarcsecond structure of a complete sample of radio sources. II – First-epoch maps at 5 GHz". The Astrophysical Journal. 328: 114. Bibcode:1988ApJ...328..114P. doi:10.1086/166274. ISSN   0004-637X.
  8. ↑ Trippe, S.; Krips, M.; Piétu, V.; Neri, R.; Winters, J. M.; Gueth, F.; Bremer, M.; Salome, P.; Moreno, R.; Boissier, J.; Fontani, F. (2011-09-01). "The long-term millimeter activity of active galactic nuclei". Astronomy & Astrophysics. 533: A97. arXiv: 1107.5456 . Bibcode:2011A&A...533A..97T. doi:10.1051/0004-6361/201015558. ISSN   0004-6361.
  9. ↑ Shaffer, D. B.; Kellermann, K. I.; Purcell, G. H.; Pauliny-Toth, I. I. K.; Preuss, E.; Witzel, A.; Graham, D.; Schilizzi, R. T.; Cohen, M. H.; Moffet, A. T.; Romney, J. D.; Niell, A. E. (1977-12-01). "The compact radio sources in 4C 39. 25 and 3C 345". The Astrophysical Journal. 218: 353–360. Bibcode:1977ApJ...218..353S. doi:10.1086/155689. ISSN   0004-637X.
  10. ↑ Baath, L. B.; Cotton, W. D.; Counselman, C. C.; Shapiro, I. I.; Wittels, J. J.; Hinteregger, H. F.; Knight, C. A.; Rogers, E. E.; Whitney, A. R.; Clark, T. A.; Hutton, L. K.; Niell, A. E. (1980-06-01). "Time-dependent radio fine structure of the compact sources NRAO 150 and 4C 39.25". Astronomy and Astrophysics. 86: 364–372. Bibcode:1980A&A....86..364B. ISSN   0004-6256.
  11. ↑ Shaffer, D. B. (1984-01-01). "4C 39.25 – A contracting sources ?". IAU Symposium. 110: 135–136.
  12. ↑ Shaffer, D. B.; Marscher, A. P. (1985-03-01). "Multi-Epoch VLBI Observations of the Quasar 4C39.25: Superluminal Motion Sandwiched by Stationery Structure". Bulletin of the American Astronomical Society. 17: 609. Bibcode:1985BAAS...17..609S.
  13. ↑ Jackson, N.; Browne, I. W. A.; Alberdi, A.; Marcaide, J. M. (1993-12-01). "The sub-arcsecond structure of 4C 39.25". Astronomy and Astrophysics. 280: 128. Bibcode:1993A&A...280..128J. ISSN   0004-6361.
  14. ↑ Wu, S. Y.; Pauliny-Toth, I. I. K.; Porcas, R. W. (1988-01-01). "The Structure of 4C39.25 on Intermediate Scales". The Impact of VLBI on Astrophysics and Geophysics; Proceedings of the 129th IAU Symposium, Cambridge, MA, May 10–15, 1987. 129: 41. Bibcode:1988IAUS..129...41W.
  15. 1 2 Marscher, Alan P.; Zhang, Yun Fei; Shaffer, David B.; Aller, Hugh D.; Aller, Margo F. (1991-04-01). "Multifrequency VLA, VLBI, and Single-Dish Observations of the Quasar 4C 39.25". The Astrophysical Journal. 371: 491. Bibcode:1991ApJ...371..491M. doi:10.1086/169912. ISSN   0004-637X.
  16. ↑ Alberdi, A.; Krichbaum, T. P.; Graham, D. A.; Greve, A.; Grewing, M.; Marcaide, J. M.; Witzel, A.; Booth, R. S.; Baath, L. B.; Colomer, F.; Doeleman, S.; Marscher, A. P.; Rogers, A. E. E.; Schalinski, C. J.; Standke, K. (1997-11-01). "The high-frequency compact radio structure of the peculiar quasar 4C 39.25". Astronomy and Astrophysics. 327: 513–521. Bibcode:1997A&A...327..513A. ISSN   0004-6361.
  17. ↑ Shaffer, David B.; Marscher, Alan P.; Marcaide, Jon; Romney, Jonathan D. (1987-03-01). "Multiepoch VLBI Observations of 4C 39.25: Superluminal Motion and Stationary Structure". The Astrophysical Journal. 314: L1. Bibcode:1987ApJ...314L...1S. doi:10.1086/184839. ISSN   0004-637X.
  18. ↑ Schalinski, C. J.; Alberdi, A.; Elósegui, P.; Marcaide, J. M. (1988-01-01). "Uniform Apparent Superluminal Motion in 4C39.25". The Impact of VLBI on Astrophysics and Geophysics; Proceedings of the 129th IAU Symposium, Cambridge, MA, May 10–15, 1987. 129: 39. Bibcode:1988IAUS..129...39S.
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