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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"

36784 results found.

  1. GRB 030204: Correction to GCN 1856
  2. GRB 030115: Optical Observations
  3. GRB 030204, optical observations
  4. IPN triangulation of GRB030204 (small error box)
  5. IPN triangulation of GRB030202 (annulus)
  6. GRB 030131, optical observations
  7. GRB030131: Kiso optical limit for corrected position
  8. GRB030131: Optical limits for corrected position
  9. GRB 030131: afterglow candidate
  10. GRB 030115, late-time optical observations
  11. GRB030131: corrected INTEGRAL position
  12. Type Ic SN2003L (SN/GRB?), optical spectrum
  13. GRB030131: Kiso Observations
  14. GRB 020819: Host galaxy at Radio Position
  15. IPN triangulation of GRB030131 - CORRECTION
  16. GRB 020819: afterglow candidate
  17. IPN triangulation of GRB030131
  18. GRB 030131 optical observations
  19. GRB 030131 optical observations
  20. A long GRB detected by INTEGRAL
  21. GRB030115: 1.2 mm upper limits with MAMBO @ IRAM 30m
  22. Type Ic SN2003L (SN/GRB?) Radio Observations
  23. IPN triangulation of GRB030127 (annulus)
  24. GRB030115 submm upper limit
  25. IPN triangulation of GRB030119 (two large error boxes)
  26. GRB 030115: Further IR observations with IRSF/SIRIUS
  27. IPN triangulation of GRB030117 (two large error boxes)
  28. Publicizing GRB Discoveries - A Message from NASA HQ
  29. GRB 030115: Radio detection of IR candidate
  30. GRB 030115, simultaneous observations by BOOTES-1
  31. GRB 030115: IR observations with IRSF/SIRIUS
  32. IPN triangulation of GRB030115C (large error box)
  33. GRB030115: R-band counterpart of IR candidate
  34. GRB030115, afterglow candidate
  35. GRB 021211: R-band observations at late-time
  36. GRB030115: Optical Observations, Swiss Telescope at La Silla (ESO, Chile)
  37. IPN triangulation of GRB030115B (small error box)
  38. GRB 030115 : Possible IR counterpart
  39. GRB 030115: Radio Observations
  40. GRB030115 (=H2533): A Long GRB Localized by the HETE WXM and SXC
  41. Distribution of INTEGRAL SPI-ACS triggers for GRB bursts
  42. IPN triangulation of GRB030115B (annulus)
  43. ANNOUNCEMENT ON INTEGRAL GRB ALERTS
  44. Distribution of INTEGRAL SPI-ACS triggers
  45. GRB030115: R-band observations at Asiago
  46. GRB030115: TAROT optical observations
  47. GRB 021211: VLT spectrum
  48. GRB 030115: APO Optical Observations
  49. GRB 030115, no optical candidate
  50. GRB 030115, optical observations
  51. GRB 030115, optical candidate
  52. Possible GRB030113 seen by SPI ACS
  53. Probable GRB030112B seen by SPI ACS
  54. Probable GRB030112 seen by SPI ACS
  55. Possible GRB030111 seen by SPI ACS
  56. Possible GRB030110b seen by SPI ACS
  57. Possible GRB 030110 seen by SPI ACS
  58. IPN triangulation of GRB030109 (annulus)
  59. IPN triangulation of GRB030105 (large error box)
  60. IPN triangulation of GRB030102B (refined localization - portion of annulus)
  61. Possible GRB 20030109 seen by SPI ACS
  62. IPN triangulation of GRB030102B (portion of annulus)
  63. IPN triangulation of GRB030102A (large error box)
  64. Possible GRB20030107 seen by SPI-ACS
  65. Possible GRB 20030105 seen by SPI ACS
  66. IPN triangulation of GRB030102 (annulus)
  67. GRB on 20030102 seen by SPI-ACS
  68. VLT spectroscopy of the probable host of GRB 021211
  69. GRB on 20030101 seen by SPI-ACS
  70. IPN triangulation of GRB030101 (two large error boxes)
  71. GRB021226
  72. GRB 021211: Probable Host and Underlying Supernova
  73. GRB 021226 registration by Helicon/Coronas-F
  74. Probable GRB in INTEGRAL SPI-ACS
  75. IPN triangulation of GRB021223 (two large error boxes)
  76. GRB021211, radio observations
  77. GRB 021112: Evidence for Another Dark Optical Afterglow
  78. GRB 021219: OSN optical observations
  79. GRB021219: Radio Observations
  80. IPN triangulation of GRB021219 - CORRECTION
  81. IPN triangulation of GRB021219
  82. GRB021219, optical observation by MASTER
  83. GRB021219: Correction to GCN 1766
  84. VLT spectra of GRB 021211 revisited
  85. GRB021219: a long GRB localized by INTEGRAL
  86. IPN detection of continued activity from SGR1806-20
  87. IPN triangulation of GRB021215 (large error box)
  88. IPN triangulation of GRB021214 (annulus)
  89. XRF 020903 : HST observations
  90. GRB 021201: Optical Observations
  91. GRB 021211, optical observations
  92. GRB 021211: CTIO observations
  93. GRB021211: Measurement of Early Time Afterglow
  94. VLT spectrum of GRB 021211
  95. IPN triangulation of GRB021211B (two large error boxes)
  96. GRB 021211: early break in light curve
  97. GRB021211, BVRI field photometry
  98. GRB 021211, IR observations
  99. GRB 021211, optical observations
  100. GRB 021211: Optical Observations

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