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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"

33672 results found.

  1. GRB 990123 optical observations
  2. GRB 990123: Pre-Burst Detection of an Apparent Host Galaxy
  3. GRB 990123 radio observations
  4. GRB 990123, new radio source
  5. GRB990123, Optical observation
  6. GRB 990123: Optical Decay Slope
  7. GRB 990123 r-band photometry
  8. GRB 990123 Optical Follow-up
  9. GRB990123, early optical counterpart detection
  10. GRB990123 Optical Observation
  11. GRB 990123: Bright New Source, Possible Optical Transient
  12. GRB 990123, Radio observations
  13. SN 1999E & GRB 980919
  14. Possible identification of SN1999E with GRB980910
  15. Optical Observations of GRB 981220
  16. GRB 981226: radio variable
  17. GRB981220
  18. GRB981220, Optical Observations
  19. GRB 981220 Optical observations
  20. GRB 981226 Optical Observations
  21. GRB 980613: Spectroscopy of the host galaxy
  22. GRB981226, sub-millimeter observations
  23. GRB981220, sub-millimeter observations
  24. GRB 981220 and GRB 981226, optical observations
  25. GRB 981226 radio observations
  26. GRB 981226
  27. GRB 981226 optical observations
  28. radio observations of GRB 981226
  29. GRB981220 B, R and I band observations
  30. GRB 981220:Optical Observations
  31. GRB 981220 optical R and I observations
  32. GRB981226, BeppoSAX Christmas GRB
  33. GRB 981226 - Infrared Observations
  34. GRB 981226 optical observations
  35. GRB 981220
  36. GRB 981220, radio observations
  37. GRB981226 Optical Observation
  38. GRB 981220, radio observations
  39. GRB 981220: BeppoSAX/GRBM results
  40. GRB981220 I-band Observations
  41. GRB 981220
  42. GRB 981220 Optical Observations
  43. GRB 981220, optical observations
  44. GRB 980326/Host Galaxy
  45. GRB981220 IPN error box
  46. GRB 981220: RXTE/ASM and BeppoSAX/GRBM results
  47. GRB980329 R,I flux calibration and R,I,K upper limits
  48. GRB980425: X-ray revised positions
  49. GRB 980923 BATSE Observations
  50. GRB980703 Very Long Baseline Interferometry
  51. GRB970508 optical observations
  52. GRB971214, association with a Galactic star?
  53. Optical Observations of the Host Galaxy of GRB 980519
  54. GRB980519, Optical Observations
  55. GRB980703, Host galaxy multicolor photometry
  56. GRB980703 - BeppoSAX/GRBM detection
  57. GRB 980703 (NFI observations)
  58. GRB980703 optical photometry
  59. GRB 980703: BATSE Observations
  60. GRB980703: Radio transient
  61. GRB980703 H-band Observations
  62. GRB 980703: Spectrum of the proposed optical counterpart
  63. RXTE Observation of GRB 980706
  64. GRB980703: Spectrum of the proposed optical counterpart
  65. GRB980703 Transient Optical Follow-Up
  66. GRB980703: LOTIS observation at early times
  67. GRB980613 Optical Observations
  68. GRB 980703
  69. GRB 980703 H-band Observations
  70. GRB980703 (optical R observations)
  71. GRB980706
  72. GRB980703: radio source/optical transient
  73. BeppoSAX NFI observations of GRB 980703
  74. GRB 980703: ASM Position & Intensity
  75. GRB980703
  76. GRB980703 optical followup
  77. GRB 980613 Near-IR observations
  78. GRB980613, optical observations
  79. GRB 980613: Optical transient and its host galaxy
  80. GRB 980613: Detection of the probable host galaxy
  81. GRB 980613: BATSE Observations
  82. GRB 980613 Optical Observations
  83. GRB 980613 optical observations
  84. GRB980613 Optical Observations
  85. GRB980613 observations from Palomar
  86. GRB980613 BeppoSAX-NFI follow up
  87. GRB 980613 new optical/IR observations
  88. GRB 980613 optical/IR obs.
  89. GRB980613 Near Infra-Red Observations
  90. GRB980611
  91. GRB980613, BeppoSAX WFC positions
  92. GRB971214 Secondary Standards
  93. GRB980519 Secondary Standards
  94. BATSE on-board GRB trigger change
  95. GRB 980519 Optical Observations
  96. GRB980519 optical observations
  97. GRB 980519
  98. GRB980519 optical observations
  99. GRB 980519 Optical Observations
  100. GRB980519 BATSE Observations

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