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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"

45409 results found.

  1. GRB990123 Optical Observation
  2. GRB990123, BeppoSAX-NFI X-ray afterglow detection
  3. GRB990123, refined SAX-WFC position
  4. GRB 990123: Bright New Source, Possible Optical Transient
  5. GRB 990123, Radio observations
  6. GRB990123, BeppoSAX WFC detection and NFI planned follow-up
  7. SN 1999E & GRB 980919
  8. Possible identification of SN1999E with GRB980910
  9. Optical Observations of GRB 981220
  10. GRB 981226: radio variable
  11. GRB981220
  12. GRB981220, Correction to GCN 179
  13. GRB981220, Optical Observations
  14. GRB 981220 Optical observations
  15. GRB 981226 Optical Observations
  16. GRB 980613: Spectroscopy of the host galaxy
  17. GRB981226, sub-millimeter observations
  18. GRB981220, sub-millimeter observations
  19. GRB 981220 and GRB 981226, optical observations
  20. GRB981226 Optical Observations
  21. GRB981226 BeppoSAX follow up
  22. GRB 981226 radio observations
  23. GRB 981226
  24. GRB 981226 optical observations
  25. radio observations of GRB 981226
  26. GRB981220 B, R and I band observations
  27. GRB981226, BeppoSAX-NFI follow-up
  28. Optical Observations of GRB981226
  29. GRB 981220:Optical Observations
  30. GRB 981220 optical R and I observations
  31. GRB981226, BeppoSAX Christmas GRB
  32. GRB 981226 - Infrared Observations
  33. GRB 981226 optical observations
  34. GRB 981220
  35. GRB 981220, radio observations
  36. GRB981226 Optical Observation
  37. GRB 981220, radio observations
  38. GRB 981220: BeppoSAX/GRBM results
  39. GRB981220 I-band Observations
  40. GRB981220 Optical 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. BeppoSAX NFI Observation of GRB980425
  48. GRB980329 R,I flux calibration and R,I,K upper limits
  49. GRB980425 Optical Follow-up
  50. GRB980425: X-ray revised positions
  51. GRB 980923 BATSE Observations
  52. SGR1900+14, BeppoSAX-GRBM observations
  53. GRB980703 Very Long Baseline Interferometry
  54. GRB970508 optical observations
  55. GRB971214, association with a Galactic star?
  56. Optical Observations of the Host Galaxy of GRB 980519
  57. GRB980519, Optical Observations
  58. GRB980703, Host galaxy multicolor photometry
  59. GRB980703 - BeppoSAX/GRBM detection
  60. GRB 980703 (NFI observations)
  61. GRB980703 optical photometry
  62. GRB 980703: BATSE Observations
  63. GRB980703 optical observations
  64. GRB980703: Radio transient
  65. GRB980703 H-band Observations
  66. GRB 980703: Spectrum of the proposed optical counterpart
  67. RXTE Observation of GRB 980706
  68. GRB980703: Spectrum of the proposed optical counterpart
  69. GRB980703 Transient Optical Follow-Up
  70. GRB980703: LOTIS observation at early times
  71. GRB980613 Optical Observations
  72. GRB 980703
  73. GRB980703 (I band observations)
  74. GRB 980703 H-band Observations
  75. GRB980703 (optical R observations)
  76. GRB980706
  77. GRB980703: radio source/optical transient
  78. BeppoSAX NFI observations of GRB 980703
  79. GRB 980703: ASM Position & Intensity
  80. GRB980703
  81. GRB980519 observation report
  82. GRB980703 optical followup
  83. SGR1627-41
  84. Radio observations of SGRs
  85. SGR1900+14 field optical observations
  86. GRB 980613 Near-IR observations
  87. GRB980613, optical observations
  88. GRB 980613: Optical transient and its host galaxy
  89. SGR1627-41, RXTE/ASM observations
  90. SGR1627-41, Refined IPN annulus location
  91. GRB 980613: Detection of the probable host galaxy
  92. Reduced error box of SGR 1627-41
  93. GRB 980613: BATSE Observations
  94. SGR1627-41, BeppoSAX-GRBM detections
  95. SGR 1627-41
  96. GRB 980613 Optical Observations
  97. GRB 980613 optical observations
  98. Discovery of a new SGR source, SGR1627-41
  99. GRB980613 Optical Observations
  100. GRB980613 observations from Palomar

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