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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"

2909 results found.

  1. GRB 030329, the review of the sky area in plate archive (1950-1998)
  2. IPN triangulation of GRB030422 (two large error boxes)
  3. GRB030329: 444 AAVSO Measurements
  4. GRB 030329, nearby galaxies
  5. Further AAVSO V,B,R observations of GRB030329
  6. GRB 030329: Correction to GCN 2056
  7. GRB 030329: optical observations
  8. GRB030323, ROTSE-III detection of possible optical counterpart
  9. GRB030323, possible optical counterpart
  10. IPN triangulation of GRB030320 (small error box)
  11. GRB030226 (=U10893): A Long GRB Localized by the HETE WXM and SXC
  12. GRB 030217: Optical Observations at 4, 5, and 6 Days
  13. GRB030131: Kiso Observations
  14. IPN triangulation of GRB030101 (two large error boxes)
  15. GRB021004, late time optical observations
  16. Improved IPN error box for GRB021125
  17. IPN BURST POSITION
  18. IPN triangulation of GRB021125 (INTEGRAL BURST)
  19. GRB021104(=H2434): A Long, X-Ray-Rich GRB Localized by HETE
  20. GRB021104: optical observations
  21. GRB021104: possible optical afterglow
  22. IPN triangulation of GRB021027 (single large error box)
  23. GRB021004, late-time optical observations
  24. GRB 021004: optical observations
  25. IPN triangulation of GRB021020
  26. GRB021016(=H2397): A Long GRB Localized by HETE
  27. IPN triangulation of GRB021016 (small error box)
  28. IPN triangulation of GRB021008 (two small error boxes)
  29. GRB021004: optical observations and predicted break time
  30. GRB021004: BVRc photometry
  31. GRB 021004: optical counterpart
  32. GRB 021004, SPM optical observations
  33. IPN triangulation of GRB020923 (two error boxes)
  34. Confirmation of IPN error box for GRB020910
  35. IPN triangulation of GRB020910
  36. GRB020903(=H2314): An X-Ray Flash Localized by HETE
  37. INTEGRAL GRBs added to GCN
  38. IPN error box for GRB020813
  39. GRB020813: Candidate Optical Afterglow
  40. Correction to IPN error box for GRB020706
  41. GRB 020625, optical observations
  42. GRB 020531: optical photometry of Chandra sources
  43. GRB020604, optical observations
  44. GRB020531: Observations with the Chandra X-ray Observatory
  45. Correction to IPN triangulation of GRB020603 (possible short/hard burst)
  46. GRB 020124: Optical observations
  47. GRB 020331 Kyoto observation on March 31
  48. GRB020317: optical observations
  49. GRB020321 optical observations
  50. IPN Upper Limits to a GRB Associated With SN2002ap
  51. GRB020127: Comparison of Chandra Epochs and Identification of Possible Counterparts
  52. GRB020127: Chandra Observations and Prospective Counterparts
  53. GRB 011211, Optical Observations
  54. GRB011130 (=XRF011130): Further analysis of Chandra Target of
  55. GRB011130 (XRF011130) Chandra Observations
  56. GRB011121: fainter still
  57. BEPPOSAX GRB011121
  58. XRF011030: Chandra Observations
  59. Millimeter observation of SGR 1900+14
  60. IPN Triangulation of GRB010412
  61. GRB010214, candidate optical afterglow
  62. GRB010214 Optical Observation
  63. IPN TRIANGULATION OF GRB010109
  64. IPN TRIANGULATION OF GRB010109
  65. XMM-Newton observation of GRB001025
  66. IPN TRIANGULATION OF GRB001020
  67. IPN TRIANGULATION OF GRB001018
  68. GRB000926 - Amateur Optical Observations
  69. GRB 000926 Chandra Observation
  70. GRB000926: X-ray afterglow by BeppoSAX. Refined analysis
  71. J and K band observations of GRB 000926
  72. GRB000926: X-ray afterglow by BeppoSAX & plan of BSAX & Chandra obs.
  73. GRB 000926, Optical Observation
  74. GRB 000926: Optical candidate
  75. Optical candidate for GRB000926
  76. GRB000911: Sub-millimeter observations
  77. IPN localization of GRB000812
  78. IPN localization of GRB000811
  79. GRB 000630: Detection of the Optical Afterglow
  80. GRB000630, Revised BVRI Field Photometry
  81. GRB000630, Optical Observations
  82. GRB000630: Optical observations
  83. possible optical counterpart of GRB 000630
  84. IPN triangulation of GRB000630
  85. GRB 000408, optical observations
  86. Radio observations of the error box of GRB000301A
  87. GRB000301A [IPN Position]
  88. GRB000226 [IPN Position]
  89. IPN localization of GRB991226
  90. GRB991216 Optical and infrared observations of Beethoven Burst
  91. GRB991216 ('Beethoven Burst') B, R, and K Observations
  92. IPN localization of GRB991208
  93. IPN localization of GRB991105
  94. IPN localization of GRB991014 - CORRECTION
  95. IPN localization of GRB991014
  96. IPN error box for GRB990915 (=BATSE 7766)
  97. GRB 990704, optical observations
  98. GRB 990506, optical observations from +1 to +3 hours
  99. GRB 990123: BVRI standards in the field
  100. GRB990123 Optical Observations

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