PKS 2004−447

PKS 2004−447
The narrow-line Seyfert galaxy PKS 2004−447
Observation data (J2000.0 epoch)
ConstellationSagittarius
Right ascension20h 07m 55.184s
Declination−44° 34′ 44.277″
Redshift0.240000
Heliocentric radial velocity71,950 km/s
Distance2.755 Gly
Apparent magnitude (V)19.3
Apparent magnitude (B)19.3
Characteristics
TypeNLSy1
Other designations
LEDA 2830329, MRC J2004−447, 2FGL J2007.9−4430, OCARS 2004−447

PKS 2004−447 is a narrow-line Seyfert 1 galaxy[1] located in the constellation of Sagittarius. It has a redshift of (z) 0.24[2] and is the radio-loudest gamma ray emitting AGN known in the southern hemisphere.[3][4] It was first identified as an astronomical radio source during a very-long-baseline interferometry survey in 1989.[5] The radio spectrum appears to be powerful and compact, making it a compact steep spectrum source.[6][7] The X-ray emission for this source is described by a simple power-law in the (0.5-10 KeV) energy range.[8]

PKS 2004−447 is classified as a blazar.[9] It is found variable on the electromagnetic spectrum and is a source of gamma ray activity.[10][11] In October 2019, it was found to exhibit a gamma ray flare,[12] reaching a highest flux of (1.3 ± 0.2) × 10−6 photon cm−2 s−1 at gamma-ray energies (0.1-300 GeV).[13] A further study also showed during the post-flare in PKS 2004−447, there was the presence of Balmer, Paschen and Helium emission lines, with these lines vanishing within a period of 1.5 years.[12]

PKS 2004−447 has a core-jet structure with angular size measuring 40 mas. Its radio emission is found mainly dominated by the radio core, accounting for 42 percent of its total flux density at 1.4 GHz. There is a jet structure emerging from the core with a projected position angle measurement of -90°, which bends to -60° at 20 mas. This jet structure is further divided into two subcomponents enveloped completely from sight by the diffused emission.[14]

The host galaxy of PKS 2004−447 is a late-type barred disk galaxy with a stellar mass of ~ 7 × 1011 Mʘ, estimated from its K-band luminosity. It has a bulge showing a relatively low Sersic index of n ~ 1.2 with a bulge-to-total ratio of (B/T = 0.39 ± 0.02) for its J-band and (B/T = 0.44 ± 0.03) for its Ks-band. These values showed the bulge PKS 2004−447 is of pseudobulge morphology.[15] The host galaxy shows two faint spiral arms[16] and has an estimated black hole mass of 9 × 107 M☉.[15]

References

  1. ^ "Fermi LAT detection of a GeV flare from the radio-loud narrow-line Seyfert 1 Galaxy PKS 2004-447". The Astronomer's Telegram. Retrieved 2024-11-04.
  2. ^ Oshlack, A. Y. K. N.; Webster, R. L.; Whiting, M. T. (2001-09-10). "A Very Radio Loud Narrow-Line Seyfert 1: PKS 2004−447". The Astrophysical Journal. 558 (2): 578–582. arXiv:astro-ph/0105213. Bibcode:2001ApJ...558..578O. doi:10.1086/322299. ISSN 0004-637X.
  3. ^ Schulz, R.; Kreikenbohm, A.; Kadler, M.; Ojha, R.; Ros, E.; Stevens, J.; Edwards, P. G.; Carpenter, B.; Elsässer, D.; Gehrels, N.; Großberger, C.; Hase, H.; Horiuchi, S.; Lovell, J. E. J.; Mannheim, K. (2016-04-01). "The gamma-ray emitting radio-loud narrow-line Seyfert 1 galaxy PKS 2004−447 - II. The radio view". Astronomy & Astrophysics. 588: A146. arXiv:1511.02631. Bibcode:2016A&A...588A.146S. doi:10.1051/0004-6361/201527404. ISSN 0004-6361.
  4. ^ Kreikenbohm, A.; Schulz, R.; Kadler, M.; Wilms, J.; Markowitz, A.; Chang, C. S.; Carpenter, B.; Elsässer, D.; Gehrels, N.; Mannheim, K.; Müller, C.; Ojha, R.; Ros, E.; Trüstedt, J. (2016-01-01). "The gamma-ray emitting radio-loud narrow-line Seyfert 1 galaxy PKS 2004−447 - I. The X-ray View". Astronomy & Astrophysics. 585: A91. arXiv:1509.03735. Bibcode:2016A&A...585A..91K. doi:10.1051/0004-6361/201424818. ISSN 0004-6361.
  5. ^ Jauncey, David L.; Savage, Ann; Morabito, David D.; Preston, Robert A.; Nicolson, George D.; Tzioumis, Anastasios K. (July 1989). "Optical identifications of southern compact radio sources". The Astronomical Journal. 98: 54. Bibcode:1989AJ.....98...54J. doi:10.1086/115127. ISSN 0004-6256.
  6. ^ Gallo, L. C.; Edwards, P. G.; Ferrero, E.; Kataoka, J.; Lewis, D. R.; Ellingsen, S. P.; Misanovic, Z.; Welsh, W. F.; Whiting, M.; Boller, T.; Brinkmann, W.; Greenhill, J.; Oshlack, A. (2006-07-21). "The spectral energy distribution of PKS 2004-447: a compact steep-spectrum source and possible radio-loud narrow-line Seyfert 1 galaxy". Monthly Notices of the Royal Astronomical Society. 370 (1): 245–254. arXiv:astro-ph/0604480. Bibcode:2006MNRAS.370..245G. doi:10.1111/j.1365-2966.2006.10482.x. ISSN 0035-8711.
  7. ^ Berton, M.; Peluso, G.; Marziani, P.; Komossa, S.; Foschini, L.; Ciroi, S.; Chen, S.; Congiu, E.; Gallo, L. C.; Björklund, I.; Crepaldi, L.; Di Mille, F.; Järvelä, E.; Kotilainen, J.; Kreikenbohm, A. (October 2021). "Hunting for the nature of the enigmatic narrow-line Seyfert 1 galaxy PKS 2004-447" (PDF). Astronomy & Astrophysics. 654: A125. arXiv:2106.12536. Bibcode:2021A&A...654A.125B. doi:10.1051/0004-6361/202141409. ISSN 0004-6361.
  8. ^ Kreikenbohm, A.; Schulz, R.; Kadler, M.; Wilms, J.; Markowitz, A.; Chang, C. S.; Carpenter, B.; Elsässer, D.; Gehrels, N.; Mannheim, K.; Müller, C.; Ojha, R.; Ros, E.; Trüstedt, J. (2015-12-23). "The gamma-ray emitting radio-loud narrow-line Seyfert 1 galaxy PKS 2004−447" (PDF). Astronomy & Astrophysics. 585: A91. arXiv:1509.03735. Bibcode:2016A&A...585A..91K. doi:10.1051/0004-6361/201424818. ISSN 0004-6361.
  9. ^ D'Abrusco, R.; Massaro, F.; Ajello, M.; Grindlay, J. E.; Smith, Howard A.; Tosti, G. (2012-03-06). "Infrared Colors Of The Gamma-Ray-Detected Blazars". The Astrophysical Journal. 748 (1): 68. arXiv:1203.0568. Bibcode:2012ApJ...748...68D. doi:10.1088/0004-637x/748/1/68. ISSN 0004-637X.
  10. ^ Berton, M.; Ciroi, S.; Congiu, E.; Chen, S.; Crepaldi, L.; Di Mille, F.; Foschini, L.; Jarvela, E.; Komossa, S.; Kotilainen, J.; Lahteenmaki, A.; Vietri, A. (2019-11-01). "Spectroscopic observations of the flaring gamma-ray narrow-line Seyfert 1 PKS 2004-447". The Astronomer's Telegram. 13259: 1. Bibcode:2019ATel13259....1B.
  11. ^ "Swift follow-up of the flaring NLSy1 PKS 2004-447". The Astronomer's Telegram. Retrieved 2024-11-04.
  12. ^ a b Hon, W.; Berton, M.; Sani, E.; Webster, R.; Wolf, C.; Rojas, A. F.; Marziani, P.; Kotilainen, J.; Congiu, E. (April 2023). "A redshifted excess in the broad emission lines after the flare of the γ-ray narrow-line Seyfert 1 PKS 2004−447" (PDF). Astronomy & Astrophysics. 672: L14. arXiv:2303.12109. Bibcode:2023A&A...672L..14H. doi:10.1051/0004-6361/202245184. ISSN 0004-6361.
  13. ^ Gokus, A.; Paliya, V. S.; Wagner, S. M.; Buson, S.; D’Ammando, F.; Edwards, P. G.; Kadler, M.; Meyer, M.; Ojha, R.; Stevens, J.; Wilms, J. (2021-05-01). "The first GeV flare of the radio-loud narrow-line Seyfert 1 galaxy PKS 2004–447". Astronomy & Astrophysics. 649: A77. arXiv:2102.11633. Bibcode:2021A&A...649A..77G. doi:10.1051/0004-6361/202039378. ISSN 0004-6361.
  14. ^ Orienti, M.; D'Ammando, F.; Larsson, J.; Finke, J.; Giroletti, M.; Dallacasa, D.; Isacsson, T.; Stoby Hoglund, J. (2015-09-14). "Investigating powerful jets in radio-loud narrow-line Seyfert 1s". Monthly Notices of the Royal Astronomical Society. 453 (4): 4038–4051. arXiv:1509.02689. doi:10.1093/mnras/stv1845. ISSN 0035-8711.
  15. ^ a b Kotilainen, Jari K.; León-Tavares, Jonathan; Olguín-Iglesias, Alejandro; Baes, Maarten; Anórve, Christopher; Chavushyan, Vahram; Carrasco, Luis (2016-11-29). "Discovery Of a Pseudobuldge Galaxy Launching Powerful Relativistic Jets". The Astrophysical Journal. 832 (2): 157. arXiv:1609.02417. Bibcode:2016ApJ...832..157K. doi:10.3847/0004-637x/832/2/157. ISSN 0004-637X.
  16. ^ Olguín-Iglesias, Alejandro; Kotilainen, Jari; Chavushyan, Vahram (2019-12-23). "The disc-like host galaxies of radio-loud narrow-line Seyfert 1s". Monthly Notices of the Royal Astronomical Society. 492 (1): 1450–1464. arXiv:1912.02746. doi:10.1093/mnras/stz3549. ISSN 0035-8711.

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