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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"

45435 results found.

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

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