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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"

45426 results found.

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

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