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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"

44454 results found.

  1. IPN triangulation of GRB030223 (annulus)
  2. IPN triangulation of GRB030220 (annulus)
  3. GRB: Non-Referencing of GCN Circulars.
  4. IPN triangulation of GRB030218 (annulus)
  5. GRB030217: optical observations
  6. IPN triangulation of GRB030217 (small error box)
  7. IPN triangulation of GRB030215C (annulus)
  8. IPN triangulation of GRB030217 (annulus)
  9. IPN triangulation of GRB030216 (annulus)
  10. IPN triangulation of GRB030215A and GRB030215B (annuli)
  11. GRB030115, WSRT radio observations - correction to GCN 1864
  12. GRB 030131: marginal optical detection
  13. GCN/INTEGRAL Mistake Fixed
  14. GRB030115, WSRT radio observations
  15. IPN triangulation of GRB030206 (annulus)
  16. IPN triangulation of GRB030208 (annulus)
  17. GRB 030204: Optical Observations
  18. GRB030204 field photometry
  19. GRB020819: Kiso R and I band observations
  20. GRB030131: Candidate Optical Afterglow
  21. GRB 030115: Optical Observations
  22. GRB 030204, optical observations
  23. IPN triangulation of GRB030204 (small error box)
  24. IPN triangulation of GRB030202 (annulus)
  25. GRB 030131, optical observations
  26. GRB030131: Kiso optical limit for corrected position
  27. GRB030131: Optical limits for corrected position
  28. GRB 030131: afterglow candidate
  29. GRB 030115, late-time optical observations
  30. GRB030131: corrected INTEGRAL position
  31. Type Ic SN2003L (SN/GRB?), optical spectrum
  32. GRB030131: Kiso Observations
  33. GRB 020819: Host galaxy at Radio Position
  34. IPN triangulation of GRB030131 - CORRECTION
  35. GRB 020819: afterglow candidate
  36. IPN triangulation of GRB030131
  37. GRB030131: Optical limit
  38. GRB 030131 optical observations
  39. GRB030131: refined position
  40. GRB 030131 optical observations
  41. A long GRB detected by INTEGRAL
  42. GRB030115: 1.2 mm upper limits with MAMBO @ IRAM 30m
  43. Type Ic SN2003L (SN/GRB?) Radio Observations
  44. IPN triangulation of GRB030127 (annulus)
  45. GRB030115 submm upper limit
  46. IPN triangulation of GRB030119 (two large error boxes)
  47. GRB 030115: Further IR observations with IRSF/SIRIUS
  48. IPN triangulation of GRB030117 (two large error boxes)
  49. Publicizing GRB Discoveries - A Message from NASA HQ
  50. GRB 030115: Radio detection of IR candidate
  51. GRB 030115, simultaneous observations by BOOTES-1
  52. GRB 030115: IR observations with IRSF/SIRIUS
  53. IPN triangulation of GRB030115C (large error box)
  54. GRB030115: R-band counterpart of IR candidate
  55. GRB030115, afterglow candidate
  56. GRB 021211: R-band observations at late-time
  57. GRB030115: Optical Observations, Swiss Telescope at La Silla (ESO, Chile)
  58. IPN triangulation of GRB030115B (small error box)
  59. GRB 030115 : Possible IR counterpart
  60. GRB 030115: Radio Observations
  61. GRB030115 (=H2533): A Long GRB Localized by the HETE WXM and SXC
  62. Distribution of INTEGRAL SPI-ACS triggers for GRB bursts
  63. IPN triangulation of GRB030115B (annulus)
  64. ANNOUNCEMENT ON INTEGRAL GRB ALERTS
  65. Distribution of INTEGRAL SPI-ACS triggers
  66. GRB030115: R-band observations at Asiago
  67. GRB030115: TAROT optical observations
  68. GRB 021211: VLT spectrum
  69. GRB 030115: APO Optical Observations
  70. GRB 030115, no optical candidate
  71. GRB 030115, optical observations
  72. GRB 030115, optical candidate
  73. Possible GRB030113 seen by SPI ACS
  74. Probable GRB030112B seen by SPI ACS
  75. Probable GRB030112 seen by SPI ACS
  76. Information about where HETE will be pointing
  77. Possible GRB030111 seen by SPI ACS
  78. Possible GRB030110b seen by SPI ACS
  79. Possible GRB 030110 seen by SPI ACS
  80. IPN triangulation of GRB030109 (annulus)
  81. IPN triangulation of GRB030105 (large error box)
  82. IPN triangulation of GRB030102B (refined localization - portion of annulus)
  83. Possible GRB 20030109 seen by SPI ACS
  84. IPN triangulation of GRB030102A - correction to peak flux
  85. IPN triangulation of GRB030102B (portion of annulus)
  86. IPN triangulation of GRB030102A (large error box)
  87. Coronas-F -Wind triangulation of GRB030102
  88. Possible GRB20030107 seen by SPI-ACS
  89. Possible GRB 20030105 seen by SPI ACS
  90. IPN triangulation of GRB030102 (annulus)
  91. GRB on 20030102 seen by SPI-ACS
  92. VLT spectroscopy of the probable host of GRB 021211
  93. GRB on 20030101 seen by SPI-ACS
  94. IPN triangulation of GRB030101 (two large error boxes)
  95. GRB021226
  96. GRB 021211: Probable Host and Underlying Supernova
  97. GRB 021226 registration by Helicon/Coronas-F
  98. Probable GRB in INTEGRAL SPI-ACS
  99. IPN triangulation of GRB021223 (two large error boxes)
  100. GRB021211, radio observations

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