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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').
  1. GRB030226 (=U10893): A Long GRB Localized by the HETE WXM and SXC
  2. GRB 030226 simultaneous optical observations
  3. Two absorption systems in GRB 030226
  4. GRB 030226, optical observations
  5. GRB030226: optical observations and refined redshift
  6. GRB030226: Optical decay index
  7. GRB 030226 Optical Spectra and R,I,z' Imaging
  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. IPN triangulation of GRB030223 (annulus)
  13. IPN triangulation of GRB030220 (annulus)
  14. GRB: Non-Referencing of GCN Circulars.
  15. IPN triangulation of GRB030218 (annulus)
  16. GRB030217: optical observations
  17. IPN triangulation of GRB030217 (small error box)
  18. IPN triangulation of GRB030215C (annulus)
  19. IPN triangulation of GRB030217 (annulus)
  20. IPN triangulation of GRB030216 (annulus)
  21. IPN triangulation of GRB030215A and GRB030215B (annuli)
  22. GRB030115, WSRT radio observations - correction to GCN 1864
  23. GRB 030131: marginal optical detection
  24. GCN/INTEGRAL Mistake Fixed
  25. GRB030115, WSRT radio observations
  26. IPN triangulation of GRB030206 (annulus)
  27. IPN triangulation of GRB030208 (annulus)
  28. GRB 030204: Optical Observations
  29. GRB030204 field photometry
  30. GRB020819: Kiso R and I band observations
  31. GRB 030204: Correction to GCN 1856
  32. GRB030131: Candidate Optical Afterglow
  33. GRB 030115: Optical Observations
  34. GRB 030204, optical observations
  35. IPN triangulation of GRB030204 (small error box)
  36. IPN triangulation of GRB030202 (annulus)
  37. GRB 030131, optical observations
  38. GRB030131: Kiso optical limit for corrected position
  39. GRB030131: Optical limits for corrected position
  40. GRB 030131: afterglow candidate
  41. GRB 030115, late-time optical observations
  42. GRB030131: corrected INTEGRAL position
  43. Type Ic SN2003L (SN/GRB?), optical spectrum
  44. GRB030131: Kiso Observations
  45. GRB 020819: Host galaxy at Radio Position
  46. IPN triangulation of GRB030131 - CORRECTION
  47. GRB 020819: afterglow candidate
  48. IPN triangulation of GRB030131
  49. GRB030131: Optical limit
  50. GRB 030131 optical observations
  51. GRB030131: refined position
  52. GRB 030131 optical observations
  53. A long GRB detected by INTEGRAL
  54. GRB030115: 1.2 mm upper limits with MAMBO @ IRAM 30m
  55. Type Ic SN2003L (SN/GRB?) Radio Observations
  56. IPN triangulation of GRB030127 (annulus)
  57. GRB030115 submm upper limit
  58. IPN triangulation of GRB030119 (two large error boxes)
  59. GRB 030115: Further IR observations with IRSF/SIRIUS
  60. IPN triangulation of GRB030117 (two large error boxes)
  61. Publicizing GRB Discoveries - A Message from NASA HQ
  62. GRB 030115: Radio detection of IR candidate
  63. GRB 030115, simultaneous observations by BOOTES-1
  64. GRB 030115: IR observations with IRSF/SIRIUS
  65. IPN triangulation of GRB030115C (large error box)
  66. GRB030115: R-band counterpart of IR candidate
  67. GRB030115, afterglow candidate
  68. GRB 021211: R-band observations at late-time
  69. GRB030115: Optical Observations, Swiss Telescope at La Silla (ESO, Chile)
  70. IPN triangulation of GRB030115B (small error box)
  71. GRB 030115 : Possible IR counterpart
  72. GRB 030115: Radio Observations
  73. GRB030115 (=H2533): A Long GRB Localized by the HETE WXM and SXC
  74. Distribution of INTEGRAL SPI-ACS triggers for GRB bursts
  75. IPN triangulation of GRB030115B (annulus)
  76. ANNOUNCEMENT ON INTEGRAL GRB ALERTS
  77. Distribution of INTEGRAL SPI-ACS triggers
  78. GRB030115: R-band observations at Asiago
  79. GRB030115: TAROT optical observations
  80. GRB 021211: VLT spectrum
  81. GRB 030115: APO Optical Observations
  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 GRB030102A - correction to peak flux
  97. IPN triangulation of GRB030102B (portion of annulus)
  98. IPN triangulation of GRB030102A (large error box)
  99. Coronas-F -Wind triangulation of GRB030102
  100. Possible GRB20030107 seen by SPI-ACS

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