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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"

2900 results found.

  1. GRB030323, ROTSE-III detection of possible optical counterpart
  2. GRB030323, possible optical counterpart
  3. IPN triangulation of GRB030320 (small error box)
  4. GRB030226 (=U10893): A Long GRB Localized by the HETE WXM and SXC
  5. GRB 030217: Optical Observations at 4, 5, and 6 Days
  6. GRB030131: Kiso Observations
  7. IPN triangulation of GRB030101 (two large error boxes)
  8. Improved IPN error box for GRB021125
  9. IPN BURST POSITION
  10. IPN triangulation of GRB021125 (INTEGRAL BURST)
  11. GRB021104(=H2434): A Long, X-Ray-Rich GRB Localized by HETE
  12. GRB021104: optical observations
  13. GRB021104: possible optical afterglow
  14. IPN triangulation of GRB021027 (single large error box)
  15. IPN triangulation of GRB021020
  16. GRB021016(=H2397): A Long GRB Localized by HETE
  17. IPN triangulation of GRB021016 (small error box)
  18. IPN triangulation of GRB021008 (two small error boxes)
  19. GRB021004: optical observations and predicted break time
  20. GRB021004: BVRc photometry
  21. GRB 021004: optical counterpart
  22. GRB 021004, SPM optical observations
  23. IPN triangulation of GRB020923 (two error boxes)
  24. IPN triangulation of GRB020914 - clarification and additional information
  25. Confirmation of IPN error box for GRB020910
  26. IPN triangulation of GRB020910
  27. GRB020903(=H2314): An X-Ray Flash Localized by HETE
  28. INTEGRAL GRBs added to GCN
  29. IPN error box for GRB020813
  30. GRB020813: Candidate Optical Afterglow
  31. Correction to IPN error box for GRB020706
  32. GRB 020625, optical observations
  33. GRB 020531: optical photometry of Chandra sources
  34. GRB020604, optical observations
  35. GRB020531: Observations with the Chandra X-ray Observatory
  36. Correction to IPN triangulation of GRB020603 (possible short/hard burst)
  37. GRB 020124: Optical observations
  38. GRB 020331 Kyoto observation on March 31
  39. GRB020317: optical observations
  40. GRB020321 optical observations
  41. IPN Upper Limits to a GRB Associated With SN2002ap
  42. GRB020127: Comparison of Chandra Epochs and Identification of Possible Counterparts
  43. GRB020127: Chandra Observations and Prospective Counterparts
  44. GRB 011211, Optical Observations
  45. GRB011130 (=XRF011130): Further analysis of Chandra Target of
  46. GRB011130 (XRF011130) Chandra Observations
  47. GRB011121: fainter still
  48. BEPPOSAX GRB011121
  49. XRF011030: Chandra Observations
  50. Millimeter observation of SGR 1900+14
  51. IPN Triangulation of GRB010412
  52. GRB010214, candidate optical afterglow
  53. GRB010214 Optical Observation
  54. IPN TRIANGULATION OF GRB010109
  55. IPN TRIANGULATION OF GRB010109
  56. XMM-Newton observation of GRB001025
  57. IPN TRIANGULATION OF GRB001020
  58. IPN TRIANGULATION OF GRB001018
  59. GRB000926 - Amateur Optical Observations
  60. GRB 000926 Chandra Observation
  61. GRB000926: X-ray afterglow by BeppoSAX. Refined analysis
  62. J and K band observations of GRB 000926
  63. GRB000926: X-ray afterglow by BeppoSAX & plan of BSAX & Chandra obs.
  64. GRB 000926, Optical Observation
  65. GRB 000926: Optical candidate
  66. Optical candidate for GRB000926
  67. GRB000911: Sub-millimeter observations
  68. IPN localization of GRB000812
  69. IPN localization of GRB000811
  70. GRB 000630: Detection of the Optical Afterglow
  71. GRB000630, Revised BVRI Field Photometry
  72. GRB000630, Optical Observations
  73. GRB000630: Optical observations
  74. possible optical counterpart of GRB 000630
  75. IPN triangulation of GRB000630
  76. GRB 000408, optical observations
  77. Radio observations of the error box of GRB000301A
  78. GRB000301A [IPN Position]
  79. GRB000226 [IPN Position]
  80. IPN localization of GRB991226
  81. GRB991216 Optical and infrared observations of Beethoven Burst
  82. GRB991216 ('Beethoven Burst') B, R, and K Observations
  83. IPN localization of GRB991208
  84. IPN localization of GRB991105
  85. IPN localization of GRB991014 - CORRECTION
  86. IPN localization of GRB991014
  87. IPN error box for GRB990915 (=BATSE 7766)
  88. GRB 990704, optical observations
  89. GRB 990506, optical observations from +1 to +3 hours
  90. GRB 990123: BVRI standards in the field
  91. GRB990123 Optical Observations
  92. GRB990123, early optical counterpart detection
  93. GRB990123, BeppoSAX WFC detection and NFI planned follow-up
  94. GRB981226, BeppoSAX Christmas GRB
  95. GRB981220 I-band Observations
  96. BATSE on-board GRB trigger change
  97. GRB980326 IPN annulus
  98. GRB980329 IPN annulus
  99. GRB 971024: Refined analysis by USNOFS Observations
  100. GRB 971024: USNO Observations

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