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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"

43594 results found.

  1. Possible break in the GRB 030226 light curve
  2. GRB 030226 : Predicted light curve
  3. GRB030226: optical observation
  4. IPN triangulation of GRB030225 (annulus)
  5. GRB 030226: Confirmed decay index
  6. GRB030226: ESI spectroscopy
  7. GRB030226 (=U10893): A Long GRB Localized by the HETE WXM and SXC
  8. GRB 030226 simultaneous optical observations
  9. GRB 030226, optical observations
  10. GRB030226: Optical decay index
  11. GRB 030226 Optical Spectra and R,I,z' Imaging
  12. GRB 030226, optical observations
  13. GRB 030226: Optical afterglow
  14. GRB030226: Candidate optical afterglow
  15. GRB 030217: Optical Observations at 4, 5, and 6 Days
  16. IPN triangulation of GRB030223 (annulus)
  17. IPN triangulation of GRB030220 (annulus)
  18. GRB: Non-Referencing of GCN Circulars.
  19. IPN triangulation of GRB030218 (annulus)
  20. GRB030217: optical observations
  21. IPN triangulation of GRB030217 (small error box)
  22. IPN triangulation of GRB030215C (annulus)
  23. IPN triangulation of GRB030217 (annulus)
  24. IPN triangulation of GRB030216 (annulus)
  25. IPN triangulation of GRB030215A and GRB030215B (annuli)
  26. GRB030115, WSRT radio observations - correction to GCN 1864
  27. GRB 030131: marginal optical detection
  28. GCN/INTEGRAL Mistake Fixed
  29. GRB030115, WSRT radio observations
  30. IPN triangulation of GRB030206 (annulus)
  31. IPN triangulation of GRB030208 (annulus)
  32. GRB 030204: Optical Observations
  33. GRB030204 field photometry
  34. GRB020819: Kiso R and I band observations
  35. GRB030131: Candidate Optical Afterglow
  36. GRB 030115: Optical Observations
  37. GRB 030204, optical observations
  38. IPN triangulation of GRB030204 (small error box)
  39. IPN triangulation of GRB030202 (annulus)
  40. GRB030131: Kiso optical limit for corrected position
  41. GRB030131: Optical limits for corrected position
  42. GRB 030131: afterglow candidate
  43. GRB 030115, late-time optical observations
  44. GRB030131: corrected INTEGRAL position
  45. Type Ic SN2003L (SN/GRB?), optical spectrum
  46. GRB030131: Kiso Observations
  47. GRB 020819: Host galaxy at Radio Position
  48. IPN triangulation of GRB030131 - CORRECTION
  49. GRB 020819: afterglow candidate
  50. IPN triangulation of GRB030131
  51. GRB030131: Optical limit
  52. GRB 030131 optical observations
  53. GRB030131: refined position
  54. GRB 030131 optical observations
  55. A long GRB detected by INTEGRAL
  56. GRB030115: 1.2 mm upper limits with MAMBO @ IRAM 30m
  57. Type Ic SN2003L (SN/GRB?) Radio Observations
  58. IPN triangulation of GRB030127 (annulus)
  59. GRB030115 submm upper limit
  60. IPN triangulation of GRB030119 (two large error boxes)
  61. GRB 030115: Further IR observations with IRSF/SIRIUS
  62. IPN triangulation of GRB030117 (two large error boxes)
  63. Publicizing GRB Discoveries - A Message from NASA HQ
  64. GRB 030115: Radio detection of IR candidate
  65. GRB 030115, simultaneous observations by BOOTES-1
  66. IPN triangulation of GRB030115C (large error box)
  67. GRB030115: R-band counterpart of IR candidate
  68. GRB030115, afterglow candidate
  69. GRB 021211: R-band observations at late-time
  70. GRB030115: Optical Observations, Swiss Telescope at La Silla (ESO, Chile)
  71. IPN triangulation of GRB030115B (small error box)
  72. GRB 030115 : Possible IR counterpart
  73. GRB 030115: Radio Observations
  74. GRB030115 (=H2533): A Long GRB Localized by the HETE WXM and SXC
  75. Distribution of INTEGRAL SPI-ACS triggers for GRB bursts
  76. IPN triangulation of GRB030115B (annulus)
  77. ANNOUNCEMENT ON INTEGRAL GRB ALERTS
  78. Distribution of INTEGRAL SPI-ACS triggers
  79. GRB030115: R-band observations at Asiago
  80. GRB030115: TAROT optical observations
  81. GRB 021211: VLT spectrum
  82. GRB 030115, no optical candidate
  83. GRB 030115, optical observations
  84. GRB 030115, optical candidate
  85. Possible GRB030113 seen by SPI ACS
  86. Probable GRB030112B seen by SPI ACS
  87. Probable GRB030112 seen by SPI ACS
  88. Information about where HETE will be pointing
  89. Possible GRB030111 seen by SPI ACS
  90. Possible GRB030110b seen by SPI ACS
  91. Possible GRB 030110 seen by SPI ACS
  92. IPN triangulation of GRB030109 (annulus)
  93. IPN triangulation of GRB030105 (large error box)
  94. IPN triangulation of GRB030102B (refined localization - portion of annulus)
  95. Possible GRB 20030109 seen by SPI ACS
  96. IPN triangulation of GRB030102B (portion of annulus)
  97. IPN triangulation of GRB030102A (large error box)
  98. Coronas-F -Wind triangulation of GRB030102
  99. Possible GRB20030107 seen by SPI-ACS
  100. Possible GRB 20030105 seen by SPI ACS

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