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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"

21325 results found.

  1. GRB 010222 BV optical observations
  2. GRB010220, Optical Observations
  3. GRB010222 R-BAND OBSERVATION
  4. GRB 010220: Near-IR Observations
  5. GRB010214 follow-up from Hanle
  6. GRB 010222: Near-IR Observations
  7. GRB 010222: Optical Observations
  8. GRB010222: Optical decay slope
  9. GRB 010214, Optical Observations
  10. GRB010222: Sub-millimeter detection
  11. GRB010222: R-band fading behavior
  12. GRB010222: Optical Observations
  13. GRB010222, radio observations
  14. GRB010222, optical observations
  15. GRB010222: BeppoSAX/NFI Observations
  16. Redshift of the Optical Transient of GRB010222
  17. GRB010214B,Gamma Ray Observations
  18. GRB010222
  19. GRB010220, Radio and Optical Observations
  20. GRB 010220, simultaneous optical observations
  21. GRB010214, candidate optical afterglow
  22. GRB010214, optical observations
  23. GRB 010214, Optical Observations
  24. GRB010213, Radio Observations
  25. GRB010213 Optical Observation
  26. GRB010213, Radio Observations
  27. J-Band Observation of GRB 010214.
  28. GRB010214, Radio Observations
  29. GRB010214, optical observations
  30. GRB010213, optical observations
  31. GRB010213, Near-IR observations
  32. Possible InfraRed Transient of GRB 010214.
  33. GRB010214 Optical Observation
  34. GRB010214: BeppoSAX/NFI Observations
  35. GRB010213 (HETE) TAROT observations
  36. GRB 010214, optical observations
  37. GRB010213 detected by HETE
  38. GRB010126, TNG R-band observations
  39. GRB010126 Optical Observations
  40. GRB010126 optical observations
  41. GRB010126: Optical observations
  42. GRB 010119, optical observations
  43. GRB010119: Optical observations
  44. Optical Observations of GRB 001018 at Keck
  45. GRB010119, Radio observations
  46. Optical observations of GRB 001018 with JCAM
  47. GRB010103, optical observations
  48. GRB 001204: Ks observations
  49. H band observation of GRB 001212
  50. GRB 001212 possible OA
  51. GRB001204: Optical observations
  52. GRB001204, Radio observations
  53. GRB 001105, further optical observations
  54. GRB001120: Gunn-i observations
  55. GRB001120: Optical observations
  56. GRB001109, optical observations
  57. GRB001120, optical observations
  58. WSRT 4.8 GHz observations of GRB001109
  59. Optical/NIR observations of GRB001109
  60. GRB 001109: deep JHK upper limits
  61. GRB001109: Optical observations
  62. GRB001109: BeppoSAX/NFI Observations
  63. GRB001109, R-band optical observations
  64. GRB001109, Radio observations
  65. GRB 991208: HST Imaging of the Host Galaxy
  66. GRB000926: R-image of the host galaxy
  67. GRB 001025B, I-band observations
  68. GRB001025B, Radio observations
  69. GRB 001025 Optical Observations
  70. GRB001007: Optical observations
  71. GRB001007, Radio observations
  72. GRB001019, Optical Observations
  73. GRB 001018, Possible Radio Afterglow
  74. GRB001018, Gamma Ray Observations
  75. V,R,I band observations of GRB000926
  76. The Likely Optical/Infrared Afterglow of GRB 001011
  77. GRB 001007, BVR-band observations
  78. GRB000926 - Amateur Optical Observations
  79. GRB001007: Optical observations
  80. GRB 000926 : the host galaxy
  81. HETE-2 Launches Successfully
  82. GRB 000926 Chandra Observation
  83. GRB000926: X-ray afterglow by BeppoSAX. Refined analysis
  84. GRB000926 - Optical observations
  85. GRB000926 - Optical observations
  86. GRB000926 - Optical observations
  87. GRB000926 - Optical observations
  88. GRB 000926: optical observations
  89. GRB 000926, Optical Observations
  90. GRB000926 - Optical observations
  91. GRB000911: optical VLT observations
  92. GRB000926 K'-band Observation
  93. GRB000926 optical observations
  94. GRB000926 - Optical observations
  95. J and K band observations of GRB 000926
  96. GRB000911 Optical Observations
  97. GRB000926: X-ray afterglow by BeppoSAX & plan of BSAX & Chandra obs.
  98. GRB000926: Optical observations
  99. GRB 000926 HST/Chandra TOO Status
  100. GRB000926, radio observations

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