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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"

20948 results found.

  1. GRB 981220 Optical observations
  2. GRB 981226 Optical Observations
  3. GRB 980613: Spectroscopy of the host galaxy
  4. GRB981226, sub-millimeter observations
  5. GRB981220, sub-millimeter observations
  6. GRB 981220 and GRB 981226, optical observations
  7. GRB981226 Optical Observations
  8. GRB 981226 radio observations
  9. GRB 981226
  10. GRB 981226 optical observations
  11. radio observations of GRB 981226
  12. GRB981220 B, R and I band observations
  13. Optical Observations of GRB981226
  14. GRB 981220:Optical Observations
  15. GRB 981220 optical R and I observations
  16. GRB981226, BeppoSAX Christmas GRB
  17. GRB 981226 - Infrared Observations
  18. GRB 981226 optical observations
  19. GRB 981220
  20. GRB 981220, radio observations
  21. GRB 981220, radio observations
  22. GRB981220 I-band Observations
  23. GRB981220 Optical Observations
  24. GRB 981220
  25. GRB 981220 Optical Observations
  26. GRB 981220, optical observations
  27. GRB 980326/Host Galaxy
  28. GRB980329 R,I flux calibration and R,I,K upper limits
  29. GRB980425 Optical Follow-up
  30. GRB980425: X-ray revised positions
  31. GRB 980923 BATSE Observations
  32. SGR1900+14, BeppoSAX-GRBM observations
  33. GRB980703 Very Long Baseline Interferometry
  34. GRB970508 optical observations
  35. Optical Observations of the Host Galaxy of GRB 980519
  36. GRB980519, Optical Observations
  37. GRB 980703 (NFI observations)
  38. GRB980703 optical photometry
  39. GRB 980703: BATSE Observations
  40. GRB980703 optical observations
  41. GRB980703 H-band Observations
  42. GRB 980703: Spectrum of the proposed optical counterpart
  43. GRB980703: Spectrum of the proposed optical counterpart
  44. GRB980613 Optical Observations
  45. GRB980703 (I band observations)
  46. GRB 980703 H-band Observations
  47. GRB980703 (optical R observations)
  48. GRB980703: radio source/optical transient
  49. BeppoSAX NFI observations of GRB 980703
  50. Radio observations of SGRs
  51. SGR1900+14 field optical observations
  52. GRB 980613 Near-IR observations
  53. GRB980613, optical observations
  54. SGR1627-41, RXTE/ASM observations
  55. GRB 980613: Detection of the probable host galaxy
  56. Reduced error box of SGR 1627-41
  57. GRB 980613: BATSE Observations
  58. GRB 980613 Optical Observations
  59. GRB 980613 optical observations
  60. Discovery of a new SGR source, SGR1627-41
  61. GRB980613 Optical Observations
  62. GRB980613 observations from Palomar
  63. GRB 980613 new optical/IR observations
  64. GRB 980613 optical/IR obs.
  65. GRB980613 Near Infra-Red Observations
  66. GRB971214 Secondary Standards
  67. SGR 1900+14
  68. GRB980519 Secondary Standards
  69. SGR1900+14
  70. SGR1900+14
  71. GRB 980519 Optical Observations
  72. GRB980519 optical observations
  73. GRB980519 I-band observations
  74. GRB 980519
  75. GRB980519 optical observations
  76. GRB 980519 Optical Observations
  77. GRB980519 BATSE Observations
  78. GRB980519 optical observations
  79. GRB980519 Optical Observations
  80. GRB980519 Optical Observations
  81. GRB980519 Optical Observations
  82. GRB 980519 Optical Observations
  83. GRB980519 optical observations
  84. GRB 980425 Radio Light Curve
  85. GRB 980425 Brightness Temperature
  86. BSAX Observations of GRB980425 field
  87. GRB980425 BATSE observations
  88. SAX J0840.7+2248 Optical Observations
  89. GRB 980425 optical observations
  90. GRB980425: optical obs.
  91. GRB980425: Radio Observations
  92. GRB 980425 optical observations
  93. report on BSAX observations of GRB980425
  94. GRB 980425 optical observations
  95. GRB980326 X-ray Observations
  96. GRB980326, optical observations
  97. GRB980326, optical observations
  98. GRB980329
  99. GRB980329 Keck K-band observations
  100. GRB980329 sub-millimeter observations

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