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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"

41686 results found.

  1. GRB030226: ESI spectroscopy
  2. GRB030226 (=U10893): A Long GRB Localized by the HETE WXM and SXC
  3. GRB 030226 simultaneous optical observations
  4. Two absorption systems in GRB 030226
  5. GRB 030226, optical observations
  6. GRB030226: optical observations and refined redshift
  7. GRB030226: Optical decay index
  8. GRB 030226, optical observations
  9. GRB 030226: Optical afterglow
  10. GRB030226: Candidate optical afterglow
  11. GRB 030217: Optical Observations at 4, 5, and 6 Days
  12. GRB: Non-Referencing of GCN Circulars.
  13. GRB030217: optical observations
  14. IPN triangulation of GRB030217 (small error box)
  15. GRB030115, WSRT radio observations - correction to GCN 1864
  16. GRB 030131: marginal optical detection
  17. GCN/INTEGRAL Mistake Fixed
  18. GRB030115, WSRT radio observations
  19. IPN triangulation of GRB030206 (annulus)
  20. GRB 030204: Optical Observations
  21. GRB030204 field photometry
  22. GRB020819: Kiso R and I band observations
  23. GRB 030204: Correction to GCN 1856
  24. GRB030131: Candidate Optical Afterglow
  25. GRB 030115: Optical Observations
  26. GRB 030204, optical observations
  27. GRB 030131, optical observations
  28. GRB030131: Kiso optical limit for corrected position
  29. GRB030131: Optical limits for corrected position
  30. GRB 030131: afterglow candidate
  31. GRB 030115, late-time optical observations
  32. GRB030131: corrected INTEGRAL position
  33. Type Ic SN2003L (SN/GRB?), optical spectrum
  34. GRB030131: Kiso Observations
  35. GRB 020819: Host galaxy at Radio Position
  36. IPN triangulation of GRB030131 - CORRECTION
  37. IPN triangulation of GRB030131
  38. GRB030131: Optical limit
  39. GRB 030131 optical observations
  40. GRB030131: refined position
  41. GRB 030131 optical observations
  42. A long GRB detected by INTEGRAL
  43. GRB030115: 1.2 mm upper limits with MAMBO @ IRAM 30m
  44. Type Ic SN2003L (SN/GRB?) Radio Observations
  45. GRB030115 submm upper limit
  46. IPN triangulation of GRB030119 (two large error boxes)
  47. GRB 030115: Further IR observations with IRSF/SIRIUS
  48. Publicizing GRB Discoveries - A Message from NASA HQ
  49. GRB 030115, simultaneous observations by BOOTES-1
  50. GRB 030115: IR observations with IRSF/SIRIUS
  51. GRB030115: R-band counterpart of IR candidate
  52. GRB030115, afterglow candidate
  53. GRB 021211: R-band observations at late-time
  54. GRB030115: Optical Observations, Swiss Telescope at La Silla (ESO, Chile)
  55. IPN triangulation of GRB030115B (small error box)
  56. GRB 030115 : Possible IR counterpart
  57. GRB 030115: Radio Observations
  58. GRB030115 (=H2533): A Long GRB Localized by the HETE WXM and SXC
  59. Distribution of INTEGRAL SPI-ACS triggers for GRB bursts
  60. ANNOUNCEMENT ON INTEGRAL GRB ALERTS
  61. Distribution of INTEGRAL SPI-ACS triggers
  62. GRB030115: R-band observations at Asiago
  63. GRB030115: TAROT optical observations
  64. GRB 021211: VLT spectrum
  65. GRB 030115: APO Optical Observations
  66. GRB 030115, no optical candidate
  67. GRB 030115, optical observations
  68. GRB 030115, optical candidate
  69. Possible GRB030113 seen by SPI ACS
  70. Probable GRB030112B seen by SPI ACS
  71. Probable GRB030112 seen by SPI ACS
  72. Information about where HETE will be pointing
  73. Possible GRB030111 seen by SPI ACS
  74. Possible GRB030110b seen by SPI ACS
  75. Possible GRB 030110 seen by SPI ACS
  76. IPN triangulation of GRB030109 (annulus)
  77. IPN triangulation of GRB030105 (large error box)
  78. IPN triangulation of GRB030102B (refined localization - portion of annulus)
  79. Possible GRB 20030109 seen by SPI ACS
  80. Coronas-F -Wind triangulation of GRB030102
  81. Possible GRB20030107 seen by SPI-ACS
  82. Possible GRB 20030105 seen by SPI ACS
  83. IPN triangulation of GRB030102 (annulus)
  84. GRB on 20030102 seen by SPI-ACS
  85. VLT spectroscopy of the probable host of GRB 021211
  86. GRB on 20030101 seen by SPI-ACS
  87. GRB021226
  88. GRB 021211: Probable Host and Underlying Supernova
  89. GRB 021226 registration by Helicon/Coronas-F
  90. Probable GRB in INTEGRAL SPI-ACS
  91. IPN triangulation of GRB021223 (two large error boxes)
  92. GRB 021112: Evidence for Another Dark Optical Afterglow
  93. GRB 021219: OSN optical observations
  94. GRB021219: Radio Observations
  95. GRB021219, optical observations
  96. IPN triangulation of GRB021219 - CORRECTION
  97. IPN triangulation of GRB021219
  98. GRB021219, optical observation by MASTER
  99. GRB021219: Correction to GCN 1766
  100. VLT spectra of GRB 021211 revisited

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