Note: this is an archived version which has been superseded. The current SNR catalogue is at http://www.mrao.cam.ac.uk/surveys/snrs/

G21.5-0.9

• Right Ascension: 18 33 33
• Declination: -10 35
• Size (/arcmin): 4
• Type: C
• Flux density at 1 GHz (/Jy): 6?
• Spectral Index: 0.0

Notes: Early observations relate to the central core only.

Radio: Filled-centre, with high frequency turnover.

X-ray: Central core, with extended, faint halo.

Distance: HI absorption indicates 5.5 kpc or more.

References:

• Wilson & Weiler 1976, A&A, 53, 89. WSRT at 5 GHz (6"×35"). ADS
• Becker & Kundu 1976, ApJ, 204, 427. NRAO interferometer at 2.7 GHz (20"×5") and 8 GHz (7"×2"), plus review of flux densities. ADS
• Altenhoff et al. 1979, A&AS, 35, 23. Effelsberg 100-m at 4.9 GHz (2'.6). ADS
• Becker & Szymkowiak 1981, ApJ, 248, L23. VLA at 5 GHz (8"), and Einstein observations. ADS
• Davelaar et al. 1986, ApJ, 300, L59. EXOSAT X-ray spectrum, and VLA HI observations. ADS
• Morsi & Reich 1987, A&AS, 69, 533. Effelsberg 100-m at 32 GHz (26".5: S=5.64±0.29 Jy). ADS
• Fürst et al. 1988, PASJ, 40, 347. NRO array at 22.3 GHz (4".4×7".3). ADS
• Salter et al. 1989, A&A, 225, 167. Observations at 90.7 (29".5: S=3.8±0.4 Jy) and 141.9 GHz (S=2.5±1.2 Jy). ADS
• Salter et al. 1989, ApJ, 338, 171. NRAO 12-m at 84.2 GHz (S=3.94±0.70 Jy), plus review of flux densities. ADS
• Asaoka & Koyama 1990, PASJ, 42, 625. Ginga X-ray spectrum. ADS
• Kassim 1992, AJ, 103, 943. VLA at 327 MHz (3'.3×3'.4: S=9 Jy). ADS
• Wallace et al. 1994, A&A, 286, 565. HI of surroundings. ADS
• Biggs & Lyne 1996, MNRAS, 282, 691. Pulsar search. ADS
• Green et al. 1997, AJ, 114, 2058. Parkes 64-m OH observations. ADS
• Slane et al. 2000, ApJ, 533, L29. Chandra observations identifying X-ray halo. ADS
• Warwick et al. 2001, A&A, 365, L248. XMM-Newton observations of X-ray halo. ADS
• Bock et al. 2001, ApJ, 561, L203. BIMA at 94 GHz (8".6×4".6). ADS
• Safi-Harb et al. 2001, ApJ, 561, 308. Chandra and other X-ray observations. ADS
• La Palombara & Mereghetti 2002, A&A, 383, 916. XMM-Newton upper limit on pulsations. ADS

Last updated: 7 Jan 2004