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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"

35987 results found.

  1. GRB 030204: Optical Observations
  2. GRB030204 field photometry
  3. GRB020819: Kiso R and I band observations
  4. GRB 030204: Correction to GCN 1856
  5. GRB 030115: Optical Observations
  6. GRB 030204, optical observations
  7. IPN triangulation of GRB030204 (small error box)
  8. IPN triangulation of GRB030202 (annulus)
  9. GRB 030131, optical observations
  10. GRB030131: Kiso optical limit for corrected position
  11. GRB030131: Optical limits for corrected position
  12. GRB 030131: afterglow candidate
  13. GRB 030115, late-time optical observations
  14. GRB030131: corrected INTEGRAL position
  15. Type Ic SN2003L (SN/GRB?), optical spectrum
  16. GRB030131: Kiso Observations
  17. GRB 020819: Host galaxy at Radio Position
  18. IPN triangulation of GRB030131 - CORRECTION
  19. GRB 020819: afterglow candidate
  20. IPN triangulation of GRB030131
  21. GRB 030131 optical observations
  22. GRB 030131 optical observations
  23. A long GRB detected by INTEGRAL
  24. GRB030115: 1.2 mm upper limits with MAMBO @ IRAM 30m
  25. Type Ic SN2003L (SN/GRB?) Radio Observations
  26. IPN triangulation of GRB030127 (annulus)
  27. GRB030115 submm upper limit
  28. IPN triangulation of GRB030119 (two large error boxes)
  29. GRB 030115: Further IR observations with IRSF/SIRIUS
  30. IPN triangulation of GRB030117 (two large error boxes)
  31. Publicizing GRB Discoveries - A Message from NASA HQ
  32. GRB 030115: Radio detection of IR candidate
  33. GRB 030115, simultaneous observations by BOOTES-1
  34. GRB 030115: IR observations with IRSF/SIRIUS
  35. IPN triangulation of GRB030115C (large error box)
  36. GRB030115: R-band counterpart of IR candidate
  37. GRB030115, afterglow candidate
  38. GRB 021211: R-band observations at late-time
  39. GRB030115: Optical Observations, Swiss Telescope at La Silla (ESO, Chile)
  40. IPN triangulation of GRB030115B (small error box)
  41. GRB 030115 : Possible IR counterpart
  42. GRB 030115: Radio Observations
  43. GRB030115 (=H2533): A Long GRB Localized by the HETE WXM and SXC
  44. Distribution of INTEGRAL SPI-ACS triggers for GRB bursts
  45. IPN triangulation of GRB030115B (annulus)
  46. ANNOUNCEMENT ON INTEGRAL GRB ALERTS
  47. Distribution of INTEGRAL SPI-ACS triggers
  48. GRB030115: R-band observations at Asiago
  49. GRB030115: TAROT optical observations
  50. GRB 021211: VLT spectrum
  51. GRB 030115: APO Optical Observations
  52. GRB 030115, no optical candidate
  53. GRB 030115, optical observations
  54. GRB 030115, optical candidate
  55. Possible GRB030113 seen by SPI ACS
  56. Probable GRB030112B seen by SPI ACS
  57. Probable GRB030112 seen by SPI ACS
  58. Possible GRB030111 seen by SPI ACS
  59. Possible GRB030110b seen by SPI ACS
  60. Possible GRB 030110 seen by SPI ACS
  61. IPN triangulation of GRB030109 (annulus)
  62. IPN triangulation of GRB030105 (large error box)
  63. IPN triangulation of GRB030102B (refined localization - portion of annulus)
  64. Possible GRB 20030109 seen by SPI ACS
  65. IPN triangulation of GRB030102B (portion of annulus)
  66. IPN triangulation of GRB030102A (large error box)
  67. Possible GRB20030107 seen by SPI-ACS
  68. Possible GRB 20030105 seen by SPI ACS
  69. IPN triangulation of GRB030102 (annulus)
  70. GRB on 20030102 seen by SPI-ACS
  71. VLT spectroscopy of the probable host of GRB 021211
  72. GRB on 20030101 seen by SPI-ACS
  73. IPN triangulation of GRB030101 (two large error boxes)
  74. GRB021226
  75. GRB 021211: Probable Host and Underlying Supernova
  76. GRB 021226 registration by Helicon/Coronas-F
  77. Probable GRB in INTEGRAL SPI-ACS
  78. IPN triangulation of GRB021223 (two large error boxes)
  79. GRB021211, radio observations
  80. GRB 021112: Evidence for Another Dark Optical Afterglow
  81. GRB 021219: OSN optical observations
  82. GRB021219: Radio Observations
  83. IPN triangulation of GRB021219 - CORRECTION
  84. IPN triangulation of GRB021219
  85. GRB021219, optical observation by MASTER
  86. GRB021219: Correction to GCN 1766
  87. VLT spectra of GRB 021211 revisited
  88. GRB021219: a long GRB localized by INTEGRAL
  89. IPN detection of continued activity from SGR1806-20
  90. IPN triangulation of GRB021215 (large error box)
  91. IPN triangulation of GRB021214 (annulus)
  92. XRF 020903 : HST observations
  93. GRB 021201: Optical Observations
  94. GRB 021211, optical observations
  95. GRB 021211: CTIO observations
  96. GRB021211: Measurement of Early Time Afterglow
  97. VLT spectrum of GRB 021211
  98. IPN triangulation of GRB021211B (two large error boxes)
  99. GRB 021211: early break in light curve
  100. GRB021211, BVRI field photometry

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