Navegar

Colección

Datos Estadísticas

Artículo

Estamos trabajando para incorporar este artículo al repositorio
Consulte el artículo en la página del editor
Consulte la política de Acceso Abierto del editor

Abstract:

We present new VLA images at 328 and 1415 MHz of the supernova remnant (SNR) W28. The image at 1415 MHz, produced after the combination of 50 separate VLA pointings and the addition of single-dish data, has an angular resolution of 88″ × 48″, with an rms noise of 5 mJy beam-1. At 328 MHz, the image has an angular resolution of 97″ × 52″ and an rms noise of 14 mJy beam-1. From these observations we reestimated the characteristic parameters of W28: angular diameter 48′, flux densities S1415 MHz = 246 Jy and S328 MHz = 425 Jy, ∑1 GHz∼1.8 × 10-20 W m-2Hz-1 sr-1, and α = -0.35 (S ∝ να). The radio spectrum has local variations which correlate with total intensity features. The brighter radio filaments have a spectral index systematically flatter than the rest. The comparison of the radio emission with images in other spectral ranges reveal several excellent correlations. We conclude that (1) the encounter of the SNR shock with a molecular cloud to the east of W28 produced enhanced synchrotron and thermal X-ray emission, compression and distortion in the radio shell, Hα filaments, and the excitation of many OH (1720 MHz) masers exactly located in the interface between the shock front and the eastern molecular cloud; and (2) the interaction of the shock front moving toward us with molecular gas located in front of it has been responsible for the formation of the bright radio filaments seen in projection in the northern half of W28 and the excitation of more OH masers. Also, excellent radio/Hα correspondence is observed toward the northwest of the SNR. The total energy in relativistic particles is estimated in 2 × 1047 ergs.

Registro:

Documento: Artículo
Título:High-resolution VLA imaging of the supernova remnant W28 at 328 and 1415 MHz
Autor:Dubner, G.M.; Velazquez, P.F.; Goss, W.M.; Holdaway, M.A.
Filiación:Inst. Astronomia y Fisica Espacio, CC 67, Sucursal 28, 1428 Buenos Aires, Argentina
National Radio Astronomy Observatory, P.O. Box 0, Socorro, NM 87801, United States
National Radio Astronomy Observatory, Building 65, 949 North Cherry Avenue, Tucson, AZ 85721-0655, United States
Instituto de Astronomía, UNAM, Cdad. Universitaria, Apdo. Postal 70-264, CP 04510, México, Mexico
Palabras clave:ISM: individual (W28); Radio continuum; Supernova remnants
Año:2000
Volumen:120
Número:4
Página de inicio:1933
Página de fin:1945
DOI: http://dx.doi.org/10.1086/301583
Título revista:Astronomical Journal
Título revista abreviado:Astron. J.
ISSN:00046256
Registro:https://bibliotecadigital.exactas.uba.ar/collection/paper/document/paper_00046256_v120_n4_p1933_Dubner

Referencias:

  • Andrews, M.D., Basart, J.P., Lamb, R.C., Becker, R.H., (1983) ApJ, 266, p. 684
  • Arikawa, Y., Tatematsu, K., Sekimoto, Y., Takahashi, T., (1999) PASJ, 51, pp. L7
  • Bell, A.R., (1978) MNRAS, 182, p. 147
  • Braun, R., (1988) Mosaicking with High Dynamic Range, , (Millimeter Array Memo No. 46) (Socorro, NM: NRAO)
  • Bykov, A.M., Chevalier, R.A., Ellison, D.C., Uvarov, Y.A., (2000) ApJ, 538, p. 203
  • Claussen, M.J., Frail, D.A., Goss, W.M., Gaume, R.A., (1997) ApJ, 489, p. 143
  • Claussen, M.J., Goss, W.M., Frail, D.A., Desai, K., (1999) ApJ, 522, p. 349
  • Cornwell, T.J., (1988) A&A, 202, p. 316
  • (1992) A&A, 261, p. 353
  • Cornwell, T.J., Briggs, D.S., Holdaway, M.A., (1996) User's Guide to SDE, , Socorro, NM: NRAO
  • Downes, D., Wilson, T.L., Bieging, J., Wink, J., (1980) A&AS, 40, p. 379
  • Drury, L.O., Aharonian, F., Völk, H.J., (1994) A&A, 287, p. 959
  • Dubner, G., Holdaway, M., Goss, W.M., Mirabel, I.F., (1998) AJ, 116, p. 1842
  • Esposito, J.A., Hunter, S.D., Kanbach, G., Sreekumar, P., (1996) ApJ, 461, p. 820
  • Frail, D.A., Kassim, N.E., Weiler, K.W., (1994) AJ, 107, p. 1120
  • Frail, D.A., Kulkarni, S.R., Vasisht, G., (1993) Nature, 365, p. 136
  • Frail, D.A., Mitchell, G.F., (1998) ApJ, 508, p. 690
  • Giacani, E.B., Dubner, G.M., Kassim, N.K., Frail, D.A., Goss, W.M., Winkler, P.F., Williams, D., (1997) AJ, 113, p. 1379
  • Goudis, C., (1976) Ap&SS, 40, p. 91
  • Green, D.A., (1998) A Catalogue of Galactic Supernova Remnants, , 1998 September version; Cambridge: Mullard Radio Astron. Obs
  • Hartman, R.C., (1999) ApJS, 123, p. 79
  • Holdaway, M.A., (1994) VLA Scientific Memo 167, Evaluation of C Array Single-Configuration Imaging, , Socorro, NM: NRAO
  • Jones, T.W., (1998) PASP, 110, p. 125
  • Kassim, N.E., (1989) ApJS, 71, p. 799
  • Kassim, N.E., Yusef-Zadeh, F., (2000) Radio Astronomy at Long Wavelengths, p. 287. , ed. R. G. Stone, K. W. Weiler, M. L. Goldstein, & J.-L. Bougeret (Washington: AGU)
  • Kovalenko, A.V., Pynzar, A.V., Udaltsov, V.A., (1994) AZh, 71, p. 92
  • Astron. Rep., 38, p. 78. , English trans
  • (1994) AZh, 71, p. 110
  • Astron. Rep., 38, p. 95. , English trans
  • Kundu, M.R., (1970) ApJ, 162, p. 17
  • Kundu, M.R., Velusamy, T., (1972) A&A, 20, p. 237
  • Long, K.S., Blair, W.P., White, R.L., Matsui, Y., (1991) ApJ, 373, p. 567
  • Manchester, R.N., D'Amico, N., Tuohy, I.R., (1985) MNRAS, 212, p. 975
  • Matsui, Y., Long, K.S., (1985) The Crab Nebula and Related Supernova Remnants, p. 211. , ed. M. C. Kafatos & R. B. C. Henry (Cambridge: Cambridge Univ. Press)
  • Milne, D.K., Wilson, T.L., (1971) A&A, 10, p. 220
  • Odenwald, S.F., Shivanandan, K., Fazio, G.G., Rengarajan, T.N., McBreen, B., Campbell, M.F., Moseley, H., (1984) ApJ, 279, p. 162
  • Pacholczyk, A.G., (1970) Radio Astrophysics, , San Francisco: Freeman
  • Reich, W., Reich, P., Fürst, E., (1990) A&AS, 83, p. 539
  • Rho, J., Petre, R., (1998) ApJ, 503, pp. L167
  • Rho, J., Petre, R., Pisarski, R., Jones, L.R., (1996) Röntgenstrahlung from the Universe, p. 273. , ed. H.-U. Zimmerman, J. Trümper & H. W. Yorke (Garching: MPE)
  • Rowell, G.P., (2000) A&A, 359, p. 337
  • Shaver, P., Goss, W.M., (1970) Australian J. Phys. Astrophys. Suppl., 14, p. 77
  • Torii, K., Tsunemi, H., Kaneda, H., Slane, P., (1996) UV and X-ray Spectroscopy of Astrophysical and Laboratory Plasmas, p. 291. , ed. by K. Yamashita & T. Watanabe (Tokyo: Universal Acad. Press)
  • Van Den Bergh, S., Marscher, A.P., Terzian, Y., (1973) ApJS, 26, p. 19
  • Velázquez, P.F., (1999), Ph.D. thesis, Univ. Buenos Aires; Wootten, A., (1981) ApJ, 245, p. 105
  • Yusef-Zadeh, F., Shure, M., Wardle, M., Kassim, N., (2000) ApJ, , in press

Citas:

---------- APA ----------
Dubner, G.M., Velazquez, P.F., Goss, W.M. & Holdaway, M.A. (2000) . High-resolution VLA imaging of the supernova remnant W28 at 328 and 1415 MHz. Astronomical Journal, 120(4), 1933-1945.
http://dx.doi.org/10.1086/301583
---------- CHICAGO ----------
Dubner, G.M., Velazquez, P.F., Goss, W.M., Holdaway, M.A. "High-resolution VLA imaging of the supernova remnant W28 at 328 and 1415 MHz" . Astronomical Journal 120, no. 4 (2000) : 1933-1945.
http://dx.doi.org/10.1086/301583
---------- MLA ----------
Dubner, G.M., Velazquez, P.F., Goss, W.M., Holdaway, M.A. "High-resolution VLA imaging of the supernova remnant W28 at 328 and 1415 MHz" . Astronomical Journal, vol. 120, no. 4, 2000, pp. 1933-1945.
http://dx.doi.org/10.1086/301583
---------- VANCOUVER ----------
Dubner, G.M., Velazquez, P.F., Goss, W.M., Holdaway, M.A. High-resolution VLA imaging of the supernova remnant W28 at 328 and 1415 MHz. Astron. J. 2000;120(4):1933-1945.
http://dx.doi.org/10.1086/301583