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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"
  1. GRB010126, TNG R-band observations
  2. GRB010126 Optical Observations
  3. GRB010126 optical observations
  4. GRB010126: Optical observations
  5. IPN TRIANGULATION OF GRB010126
  6. IPN/RXTE TRIANGULATION OF GRB010126
  7. GRB 010119, optical observations
  8. GRB010119: Optical observations
  9. Optical Observations of GRB 001018 at Keck
  10. GRB010119, Radio observations
  11. IPN TRIANGULATION OF GRB010119 (SHORT/HARD)
  12. Optical observations of GRB 001018 with JCAM
  13. IPN TRIANGULATION OF GRB010115
  14. IPN TRIANGULATION OF GRB010109
  15. IPN TRIANGULATION OF GRB010109
  16. GRB010103, optical observations
  17. IPN triangulation of GRB010104
  18. IPN triangulation of GRB010103
  19. GRB 001204: Ks observations
  20. H band observation of GRB 001212
  21. GRB & BeppoSAX: ground operations restored back to 24 hrs a day
  22. IPN triangulation of GRB001219
  23. GRB 001212 Optical Observation
  24. GRB 001212 Optical Observation
  25. GRB 001212 optical observation
  26. GRB 001212 possible OA in 2MASS
  27. GRB 001212 possible OA
  28. IPN triangulation of GRB001212
  29. GRB001204: Optical observations
  30. Confirmation of IPN position for GRB001204
  31. GRB001204, Radio observations
  32. IPN triangulation of GRB001204 (short/hard)
  33. GRB 001105, further optical observations
  34. GRB001120: Gunn-i observations
  35. GRB001120: Optical observations
  36. GRB001109, optical observations
  37. GRB001120, optical observations
  38. WSRT 4.8 GHz observations of GRB001109
  39. IPN triangulation of GRB001120
  40. Optical/NIR observations of GRB001109
  41. GRB 001109: deep JHK upper limits
  42. GRB 001109 X-ray afterglow with BeppoSAX
  43. CORRECTION to XMM-Newton observation of GRB001025
  44. GRB001109: Optical observations
  45. GRB001109: BeppoSAX/NFI Observations
  46. GRB001109, R-band optical observations
  47. GRB001109, Radio observations
  48. GRB001109: BeppoSAX refined WFC position
  49. BeppoSAX ALERT: GRB001109
  50. GRB001105 BVRI field photometry correction
  51. GRB001105, BVRI field photometry
  52. GRB 001105, R-band observation
  53. IPN TRIANGULATION OF GRB001105
  54. GRB 001025B, Optical obervations
  55. GRB 991208: HST Imaging of the Host Galaxy
  56. GRB000926: R-image of the host galaxy
  57. GRB 001025B, I-band observations
  58. XMM-Newton observation of GRB001025
  59. GRB001025B, Radio observations
  60. GRB 001025 Optical Observations
  61. GRB 001025A, optical observation
  62. IPN TRIANGULATION OF GRB001025B (SHORT/HARD)
  63. CORRECTION TO IPN/RXTE ERROR BOX FOR GRB001025
  64. IPN triangulation of GRB001025
  65. GRB001007: Optical observations
  66. ASM Localization of GRB 001025
  67. GRB001007, Radio observations
  68. IPN TRIANGULATION OF GRB001020
  69. GRB001019, Optical Observations
  70. GRB 001018, Possible Radio Afterglow
  71. GRB001018, Gamma Ray Observations
  72. IPN TRIANGULATION OF GRB001019
  73. CORRECTION TO PEAK FLUX OF GRB001018
  74. IPN TRIANGULATION OF GRB001018
  75. IPN TRIANGULATION OF GRB 001017
  76. GRB 000926: Improved Absorber Redshift
  77. V,R,I band observations of GRB000926
  78. The Likely Optical/Infrared Afterglow of GRB 001011
  79. HETE positions added to GCN
  80. GRB001011 BeppoSAX/WFC refined position
  81. BeppoSAX ALERT: GRB001011
  82. GRB 001007, BVR-band observations
  83. GRB000926 - Amateur Optical Observations
  84. GRB001007: Optical observations
  85. CONCAM null result on GRB001005
  86. IPN triangulation of GRB001007
  87. GRB 000926 : the host galaxy
  88. HETE-2 Launches Successfully
  89. IPN triangulation of GRB001005
  90. HETE-2 48 hour Launch Delay
  91. GRB 000926 Chandra Observation
  92. IPN triangulation of GRB 001004
  93. Public availability of BeppoSAX data of GRB000926
  94. GRB000926: X-ray afterglow by BeppoSAX: revised fluxes (fwd)
  95. GRB000926: X-ray afterglow by BeppoSAX. Refined analysis
  96. GRB000926 - Optical observations
  97. GRB000926 - Optical observations
  98. GRB 000926, Optical Decay
  99. GRB000911: VLT infrared observation
  100. GRB000926 - Optical observations

Advanced

Download all Circulars as a .tar.gz archive (updated once a day):
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