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GCN Circulars

GCN Circulars are rapid astronomical bulletins submitted by and distributed to community members worldwide. They are used to share discoveries, observations, quantitative near-term predictions, requests for follow-up observations, or future observing plans related to high-energy, multi-messenger, and variable or transient astrophysical events. See the documentation for help with subscribing to or submitting Circulars.

Search for Circulars by submitter, subject, or body text (e.g. 'Fermi GRB').
To navigate to a specific circular, enter the associated Circular ID (e.g. 'gcn123', 'Circular 123', or '123').
Advanced Search

To narrow the search results, use advanced search syntax. This allows for specifying which circular field to search (submitter, subject, and/or body). For additional information, refer to the advanced search documentation.

Advanced Search Examples (click to copy):

subject:"Swift"
body:"GRB"
submitter:"Judith Racusin"

2794 results found.

  1. New IPN localization of GRB000529
  2. GRB000508B, optical photometry
  3. Possible GRB-related phenomenon
  4. BATSE observations of FXT/GRB 000416 = 1SAXJ1715.0-7134
  5. Refined IPN error box for GRB000408
  6. GRB000408 [IPN Position]
  7. GRB000315 [IPN Positions]
  8. GRB 000301C: Optical Spectrum and Redshift
  9. GRB 000301C: Optical Spectrum and Redshift
  10. GRB 000301C: A Precise Redshift Determination
  11. IPN error box for GRB000307
  12. GRB000301C - Host galaxy not detected in R (?)
  13. GRB000301C, near-infrared observations (JHK' imaging)
  14. GRB000301C, optical observations
  15. GRB000301C, near-infrared observations (JHK' photometry)
  16. GRB 000301A, Radio Observations
  17. GRB000226 [IPN Position]
  18. IPN annulus for GRB000214
  19. Correction to Chandra Position of GRB000210 afterglow
  20. GRB000210: possible afterglow detection with BeppoSAX NFI
  21. BATSE+IPN location of GRB000131
  22. BATSE location of GRB000126
  23. IPN localization of GRB000126
  24. GRB991216 late optical observation
  25. BEPPOSAX GRBM Localization of GRB991226
  26. IPN error boxes for GRB991229
  27. IPN localization of GRB991226
  28. IPN error boxes for GRB991221
  29. IPN error box for GRB991216
  30. GRB991216 Optical and IR observations
  31. GRB 991216 Optical Observations
  32. GRB 991216, optical observations
  33. GRB991208, optical observations
  34. GRB 991106 Optical Observations
  35. GRB 991014, Optical Observations
  36. GRB990907 and 990908
  37. GRB 990806, Optical Observations
  38. GRB990806: possible X-ray afterglow, BeppoSAX
  39. GRB990705: No Evidence for Neutrino Signal
  40. BeppoSAX GRB990705: possible X-ray afterglow
  41. GRB 990704, optical observations
  42. GRB990704
  43. GRB990704
  44. GRB990704: possible X-ray afterglow
  45. Identification of a possible optical counterpart for GRB990704
  46. GRB 990510 optical observations
  47. GRB990510: NFI X-ray source
  48. GRB 990510 optical observations
  49. Refined IPN error box for GRB990506
  50. GRB 990506: Limits on the possible optical transient
  51. GRB 990506, armchair astronomy
  52. GRB 970228: Redshift and properties of the host galaxy
  53. GRB981220 VLBA observations
  54. GRB990321 REFINED IPN ANNULUS
  55. GRB990321 IPN TRIANGULATION
  56. GRB 990316 Optical Observations
  57. GRB990316: simultaneous optical observation
  58. ASM/IPN error box for GRB 990308 (BATSE #7457)
  59. GRB990308, Possible new SGR~0209+70
  60. GRB981220, IPN localization
  61. GRB 981220, radio observations
  62. GRB 990123: Updated Keck Spectroscopy Results
  63. GRB990123, Optical observation
  64. GRB 990123: New Constraints on Possible Foreground Galaxies
  65. Search for Potential Images of GRB 990123
  66. Search for Potential Images of GRB 990123
  67. GRB990123 IPN annulus
  68. GRB 990123 : Multiple and Distorted Images of the Host Galaxy?
  69. GRB 990123 Spectroscopic Redshifts
  70. GRB 990123: Possible Gravitationally Lensed Burst?
  71. GRB 990123 optical observations
  72. GRB 990123: Bright New Source, Possible Optical Transient
  73. Possible identification of SN1999E with GRB980910
  74. GRB981220
  75. GRB 981226 optical observations
  76. GRB 981220
  77. GRB980703: Radio transient
  78. SGR1627-41, Refined IPN annulus location
  79. Reduced error box of SGR 1627-41
  80. SGR 1627-41
  81. SGR1900+14
  82. SGR1900+14
  83. GRB980519 optical observations
  84. GRB980519 Optical Observations
  85. GRB 980425 Brightness Temperature
  86. GRB980329 infrared observations
  87. Optical Observations of the GRB 971227 field
  88. GRB971227: Plaskett R-band observations
  89. GRB 971227: Optical clarifications
  90. GRB 971214: Redshift from Keck Optical Observations
  91. GRB 971214: USNOFS Observations Summary
  92. IRAS 18119-1342 and the possible new SGR
  93. Possible new SGR from US Naval Observatory
  94. GRB 970828: Palomar Observations

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