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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"

41682 results found.

  1. GRB 030226, optical observations
  2. GRB030226: optical observations and refined redshift
  3. GRB030226: Optical decay index
  4. GRB 030226, optical observations
  5. GRB 030226: Optical afterglow
  6. GRB030226: Candidate optical afterglow
  7. GRB 030217: Optical Observations at 4, 5, and 6 Days
  8. GRB: Non-Referencing of GCN Circulars.
  9. GRB030217: optical observations
  10. IPN triangulation of GRB030217 (small error box)
  11. GRB030115, WSRT radio observations - correction to GCN 1864
  12. GRB 030131: marginal optical detection
  13. GCN/INTEGRAL Mistake Fixed
  14. GRB030115, WSRT radio observations
  15. IPN triangulation of GRB030206 (annulus)
  16. GRB 030204: Optical Observations
  17. GRB030204 field photometry
  18. GRB020819: Kiso R and I band observations
  19. GRB 030204: Correction to GCN 1856
  20. GRB030131: Candidate Optical Afterglow
  21. GRB 030115: Optical Observations
  22. GRB 030204, optical observations
  23. GRB 030131, optical observations
  24. GRB030131: Kiso optical limit for corrected position
  25. GRB030131: Optical limits for corrected position
  26. GRB 030131: afterglow candidate
  27. GRB 030115, late-time optical observations
  28. GRB030131: corrected INTEGRAL position
  29. Type Ic SN2003L (SN/GRB?), optical spectrum
  30. GRB030131: Kiso Observations
  31. GRB 020819: Host galaxy at Radio Position
  32. IPN triangulation of GRB030131 - CORRECTION
  33. IPN triangulation of GRB030131
  34. GRB030131: Optical limit
  35. GRB 030131 optical observations
  36. GRB030131: refined position
  37. GRB 030131 optical observations
  38. A long GRB detected by INTEGRAL
  39. GRB030115: 1.2 mm upper limits with MAMBO @ IRAM 30m
  40. Type Ic SN2003L (SN/GRB?) Radio Observations
  41. GRB030115 submm upper limit
  42. IPN triangulation of GRB030119 (two large error boxes)
  43. GRB 030115: Further IR observations with IRSF/SIRIUS
  44. Publicizing GRB Discoveries - A Message from NASA HQ
  45. GRB 030115, simultaneous observations by BOOTES-1
  46. GRB 030115: IR observations with IRSF/SIRIUS
  47. GRB030115: R-band counterpart of IR candidate
  48. GRB030115, afterglow candidate
  49. GRB 021211: R-band observations at late-time
  50. GRB030115: Optical Observations, Swiss Telescope at La Silla (ESO, Chile)
  51. IPN triangulation of GRB030115B (small error box)
  52. GRB 030115 : Possible IR counterpart
  53. GRB 030115: Radio Observations
  54. GRB030115 (=H2533): A Long GRB Localized by the HETE WXM and SXC
  55. Distribution of INTEGRAL SPI-ACS triggers for GRB bursts
  56. ANNOUNCEMENT ON INTEGRAL GRB ALERTS
  57. Distribution of INTEGRAL SPI-ACS triggers
  58. GRB030115: R-band observations at Asiago
  59. GRB030115: TAROT optical observations
  60. GRB 021211: VLT spectrum
  61. GRB 030115: APO Optical Observations
  62. GRB 030115, no optical candidate
  63. GRB 030115, optical observations
  64. GRB 030115, optical candidate
  65. Possible GRB030113 seen by SPI ACS
  66. Probable GRB030112B seen by SPI ACS
  67. Probable GRB030112 seen by SPI ACS
  68. Information about where HETE will be pointing
  69. Possible GRB030111 seen by SPI ACS
  70. Possible GRB030110b seen by SPI ACS
  71. Possible GRB 030110 seen by SPI ACS
  72. IPN triangulation of GRB030109 (annulus)
  73. IPN triangulation of GRB030105 (large error box)
  74. IPN triangulation of GRB030102B (refined localization - portion of annulus)
  75. Possible GRB 20030109 seen by SPI ACS
  76. Coronas-F -Wind triangulation of GRB030102
  77. Possible GRB20030107 seen by SPI-ACS
  78. Possible GRB 20030105 seen by SPI ACS
  79. IPN triangulation of GRB030102 (annulus)
  80. GRB on 20030102 seen by SPI-ACS
  81. VLT spectroscopy of the probable host of GRB 021211
  82. GRB on 20030101 seen by SPI-ACS
  83. GRB021226
  84. GRB 021211: Probable Host and Underlying Supernova
  85. GRB 021226 registration by Helicon/Coronas-F
  86. Probable GRB in INTEGRAL SPI-ACS
  87. IPN triangulation of GRB021223 (two large error boxes)
  88. GRB 021112: Evidence for Another Dark Optical Afterglow
  89. GRB 021219: OSN optical observations
  90. GRB021219: Radio Observations
  91. GRB021219, optical observations
  92. IPN triangulation of GRB021219 - CORRECTION
  93. IPN triangulation of GRB021219
  94. GRB021219, optical observation by MASTER
  95. GRB021219: Correction to GCN 1766
  96. VLT spectra of GRB 021211 revisited
  97. GRB021219: a long GRB localized by INTEGRAL
  98. GRB021211: APO optical observations
  99. IPN detection of continued activity from SGR1806-20
  100. XRF 020903 : HST observations

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