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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"

45664 results found.

  1. IPN triangulation of GRB030208 (annulus)
  2. GRB 030204: Optical Observations
  3. GRB030204 field photometry
  4. GRB020819: Kiso R and I band observations
  5. GRB 030204: Correction to GCN 1856
  6. GRB030131: Candidate Optical Afterglow
  7. GRB 030115: Optical Observations
  8. GRB 030204, optical observations
  9. IPN triangulation of GRB030204 (small error box)
  10. IPN triangulation of GRB030202 (annulus)
  11. GRB 030131, optical observations
  12. GRB030131: Kiso optical limit for corrected position
  13. GRB030131: Optical limits for corrected position
  14. GRB 030131: afterglow candidate
  15. GRB 030115, late-time optical observations
  16. GRB030131: corrected INTEGRAL position
  17. Type Ic SN2003L (SN/GRB?), optical spectrum
  18. GRB030131: Kiso Observations
  19. GRB 020819: Host galaxy at Radio Position
  20. IPN triangulation of GRB030131 - CORRECTION
  21. GRB 020819: afterglow candidate
  22. IPN triangulation of GRB030131
  23. GRB030131: Optical limit
  24. GRB 030131 optical observations
  25. GRB030131: refined position
  26. GRB 030131 optical observations
  27. A long GRB detected by INTEGRAL
  28. GRB030115: 1.2 mm upper limits with MAMBO @ IRAM 30m
  29. Type Ic SN2003L (SN/GRB?) Radio Observations
  30. IPN triangulation of GRB030127 (annulus)
  31. GRB030115 submm upper limit
  32. IPN triangulation of GRB030119 (two large error boxes)
  33. GRB 030115: Further IR observations with IRSF/SIRIUS
  34. IPN triangulation of GRB030117 (two large error boxes)
  35. Publicizing GRB Discoveries - A Message from NASA HQ
  36. GRB 030115: Radio detection of IR candidate
  37. GRB 030115, simultaneous observations by BOOTES-1
  38. GRB 030115: IR observations with IRSF/SIRIUS
  39. IPN triangulation of GRB030115C (large error box)
  40. GRB030115: R-band counterpart of IR candidate
  41. GRB030115, afterglow candidate
  42. GRB 021211: R-band observations at late-time
  43. GRB030115: Optical Observations, Swiss Telescope at La Silla (ESO, Chile)
  44. IPN triangulation of GRB030115B (small error box)
  45. GRB 030115 : Possible IR counterpart
  46. GRB 030115: Radio Observations
  47. GRB030115 (=H2533): A Long GRB Localized by the HETE WXM and SXC
  48. Distribution of INTEGRAL SPI-ACS triggers for GRB bursts
  49. IPN triangulation of GRB030115B (annulus)
  50. ANNOUNCEMENT ON INTEGRAL GRB ALERTS
  51. Distribution of INTEGRAL SPI-ACS triggers
  52. GRB030115: R-band observations at Asiago
  53. GRB030115: TAROT optical observations
  54. GRB 021211: VLT spectrum
  55. GRB 030115: APO Optical Observations
  56. GRB 030115, no optical candidate
  57. GRB 030115, optical observations
  58. GRB 030115, optical candidate
  59. Possible GRB030113 seen by SPI ACS
  60. Probable GRB030112B seen by SPI ACS
  61. Probable GRB030112 seen by SPI ACS
  62. Information about where HETE will be pointing
  63. Possible GRB030111 seen by SPI ACS
  64. Possible GRB030110b seen by SPI ACS
  65. Possible GRB 030110 seen by SPI ACS
  66. IPN triangulation of GRB030109 (annulus)
  67. IPN triangulation of GRB030105 (large error box)
  68. IPN triangulation of GRB030102B (refined localization - portion of annulus)
  69. Possible GRB 20030109 seen by SPI ACS
  70. IPN triangulation of GRB030102A - correction to peak flux
  71. IPN triangulation of GRB030102B (portion of annulus)
  72. IPN triangulation of GRB030102A (large error box)
  73. Coronas-F -Wind triangulation of GRB030102
  74. Possible GRB20030107 seen by SPI-ACS
  75. Possible GRB 20030105 seen by SPI ACS
  76. IPN triangulation of GRB030102 (annulus)
  77. GRB on 20030102 seen by SPI-ACS
  78. VLT spectroscopy of the probable host of GRB 021211
  79. GRB on 20030101 seen by SPI-ACS
  80. IPN triangulation of GRB030101 (two large error boxes)
  81. GRB021226
  82. GRB 021211: Probable Host and Underlying Supernova
  83. GRB 021226 registration by Helicon/Coronas-F
  84. Probable GRB in INTEGRAL SPI-ACS
  85. IPN triangulation of GRB021223 (two large error boxes)
  86. GRB021211, radio observations
  87. GRB 021112: Evidence for Another Dark Optical Afterglow
  88. GRB 021219: OSN optical observations
  89. GRB021219: Radio Observations
  90. GRB021219, optical observations
  91. IPN triangulation of GRB021219 - CORRECTION
  92. IPN triangulation of GRB021219
  93. GRB021219, optical observation by MASTER
  94. GRB021219: Correction to GCN 1766
  95. GRB021219 refined position with INTEGRAL
  96. VLT spectra of GRB 021211 revisited
  97. GRB021219: a long GRB localized by INTEGRAL
  98. GRB021211: APO optical observations
  99. IPN detection of continued activity from SGR1806-20
  100. IPN triangulation of GRB021215 (large error box)

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