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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"

45440 results found.

  1. GCN/INTEGRAL Mistake Fixed
  2. GRB030115, WSRT radio observations
  3. IPN triangulation of GRB030206 (annulus)
  4. IPN triangulation of GRB030208 (annulus)
  5. GRB 030204: Optical Observations
  6. GRB030204 field photometry
  7. GRB020819: Kiso R and I band observations
  8. GRB030131: Candidate Optical Afterglow
  9. GRB 030115: Optical Observations
  10. GRB 030204, optical observations
  11. IPN triangulation of GRB030204 (small error box)
  12. IPN triangulation of GRB030202 (annulus)
  13. GRB 030131, optical observations
  14. GRB030131: Kiso optical limit for corrected position
  15. GRB030131: Optical limits for corrected position
  16. GRB 030131: afterglow candidate
  17. GRB 030115, late-time optical observations
  18. GRB030131: corrected INTEGRAL position
  19. Type Ic SN2003L (SN/GRB?), optical spectrum
  20. GRB030131: Kiso Observations
  21. GRB 020819: Host galaxy at Radio Position
  22. IPN triangulation of GRB030131 - CORRECTION
  23. GRB 020819: afterglow candidate
  24. IPN triangulation of GRB030131
  25. GRB030131: Optical limit
  26. GRB 030131 optical observations
  27. GRB030131: refined position
  28. GRB 030131 optical observations
  29. A long GRB detected by INTEGRAL
  30. GRB030115: 1.2 mm upper limits with MAMBO @ IRAM 30m
  31. Type Ic SN2003L (SN/GRB?) Radio Observations
  32. IPN triangulation of GRB030127 (annulus)
  33. GRB030115 submm upper limit
  34. IPN triangulation of GRB030119 (two large error boxes)
  35. GRB 030115: Further IR observations with IRSF/SIRIUS
  36. IPN triangulation of GRB030117 (two large error boxes)
  37. Publicizing GRB Discoveries - A Message from NASA HQ
  38. GRB 030115: Radio detection of IR candidate
  39. GRB 030115, simultaneous observations by BOOTES-1
  40. GRB 030115: IR observations with IRSF/SIRIUS
  41. IPN triangulation of GRB030115C (large error box)
  42. GRB030115: R-band counterpart of IR candidate
  43. GRB030115, afterglow candidate
  44. GRB 021211: R-band observations at late-time
  45. GRB030115: Optical Observations, Swiss Telescope at La Silla (ESO, Chile)
  46. IPN triangulation of GRB030115B (small error box)
  47. GRB 030115 : Possible IR counterpart
  48. GRB 030115: Radio Observations
  49. GRB030115 (=H2533): A Long GRB Localized by the HETE WXM and SXC
  50. Distribution of INTEGRAL SPI-ACS triggers for GRB bursts
  51. IPN triangulation of GRB030115B (annulus)
  52. ANNOUNCEMENT ON INTEGRAL GRB ALERTS
  53. Distribution of INTEGRAL SPI-ACS triggers
  54. GRB030115: R-band observations at Asiago
  55. GRB030115: TAROT optical observations
  56. GRB 021211: VLT spectrum
  57. GRB 030115: APO Optical Observations
  58. GRB 030115, no optical candidate
  59. GRB 030115, optical observations
  60. GRB 030115, optical candidate
  61. Possible GRB030113 seen by SPI ACS
  62. Probable GRB030112B seen by SPI ACS
  63. Probable GRB030112 seen by SPI ACS
  64. Information about where HETE will be pointing
  65. Possible GRB030111 seen by SPI ACS
  66. Possible GRB030110b seen by SPI ACS
  67. Possible GRB 030110 seen by SPI ACS
  68. IPN triangulation of GRB030109 (annulus)
  69. IPN triangulation of GRB030105 (large error box)
  70. IPN triangulation of GRB030102B (refined localization - portion of annulus)
  71. Possible GRB 20030109 seen by SPI ACS
  72. IPN triangulation of GRB030102A - correction to peak flux
  73. IPN triangulation of GRB030102B (portion of annulus)
  74. IPN triangulation of GRB030102A (large error box)
  75. Coronas-F -Wind triangulation of GRB030102
  76. Possible GRB20030107 seen by SPI-ACS
  77. Possible GRB 20030105 seen by SPI ACS
  78. IPN triangulation of GRB030102 (annulus)
  79. GRB on 20030102 seen by SPI-ACS
  80. VLT spectroscopy of the probable host of GRB 021211
  81. GRB on 20030101 seen by SPI-ACS
  82. IPN triangulation of GRB030101 (two large error boxes)
  83. GRB021226
  84. GRB 021211: Probable Host and Underlying Supernova
  85. GRB 021226 registration by Helicon/Coronas-F
  86. Probable GRB in INTEGRAL SPI-ACS
  87. IPN triangulation of GRB021223 (two large error boxes)
  88. GRB021211, radio observations
  89. GRB 021112: Evidence for Another Dark Optical Afterglow
  90. GRB 021219: OSN optical observations
  91. GRB021219: Radio Observations
  92. GRB021219, optical observations
  93. IPN triangulation of GRB021219 - CORRECTION
  94. IPN triangulation of GRB021219
  95. GRB021219, optical observation by MASTER
  96. GRB021219: Correction to GCN 1766
  97. GRB021219 refined position with INTEGRAL
  98. VLT spectra of GRB 021211 revisited
  99. GRB021219: a long GRB localized by INTEGRAL
  100. GRB021211: APO optical observations

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