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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"

37731 results found.

  1. 030302: NOT A GRB
  2. 030228: NOT A GRB
  3. GRB 030228, optical observations
  4. GRB 030226: Steep Decline
  5. GRB 030227: Confirmed Optical Afterglow (S1-A)
  6. GRB 030226: R band polarimetric observations
  7. GRB 030226: Optical observations
  8. GRB 030227: fading of candidate optical afterglow 'S1-A'
  9. GRB030227:Optical observations
  10. GRB 20030226: Upper limits from recent and historical observations
  11. GRB 030227, possible optical counterpart of XMM-Newton source
  12. GRB030227 - faint tentative OT candidate
  13. GRB 030226, optical observations
  14. GRB030227: Kiso optical observations
  15. GRB 030227: Kyoto optical observation
  16. GRB 030226, optical light curve
  17. GRB 030226 spectroscopy
  18. Possible break in the GRB 030226 light curve
  19. GRB 030226 : Predicted light curve
  20. IPN triangulation of GRB030225 (annulus)
  21. GRB 030226: Confirmed decay index
  22. GRB030226: ESI spectroscopy
  23. GRB030226 (=U10893): A Long GRB Localized by the HETE WXM and SXC
  24. GRB 030226 simultaneous optical observations
  25. Two absorption systems in GRB 030226
  26. GRB 030226, optical observations
  27. GRB 030226 Optical Spectra and R,I,z' Imaging
  28. GRB 030226, optical observations
  29. GRB 030226: Optical afterglow
  30. GRB 030217: Optical Observations at 4, 5, and 6 Days
  31. IPN triangulation of GRB030223 (annulus)
  32. IPN triangulation of GRB030220 (annulus)
  33. GRB: Non-Referencing of GCN Circulars.
  34. IPN triangulation of GRB030218 (annulus)
  35. IPN triangulation of GRB030217 (small error box)
  36. IPN triangulation of GRB030215C (annulus)
  37. IPN triangulation of GRB030217 (annulus)
  38. IPN triangulation of GRB030216 (annulus)
  39. IPN triangulation of GRB030215A and GRB030215B (annuli)
  40. GRB030115, WSRT radio observations - correction to GCN 1864
  41. GRB 030131: marginal optical detection
  42. GRB030115, WSRT radio observations
  43. IPN triangulation of GRB030206 (annulus)
  44. IPN triangulation of GRB030208 (annulus)
  45. GRB 030204: Optical Observations
  46. GRB030204 field photometry
  47. GRB020819: Kiso R and I band observations
  48. GRB 030204: Correction to GCN 1856
  49. GRB 030115: Optical Observations
  50. GRB 030204, optical observations
  51. IPN triangulation of GRB030204 (small error box)
  52. IPN triangulation of GRB030202 (annulus)
  53. GRB 030131, optical observations
  54. GRB030131: Kiso optical limit for corrected position
  55. GRB030131: Optical limits for corrected position
  56. GRB 030131: afterglow candidate
  57. GRB 030115, late-time optical observations
  58. GRB030131: corrected INTEGRAL position
  59. Type Ic SN2003L (SN/GRB?), optical spectrum
  60. GRB030131: Kiso Observations
  61. GRB 020819: Host galaxy at Radio Position
  62. IPN triangulation of GRB030131 - CORRECTION
  63. GRB 020819: afterglow candidate
  64. IPN triangulation of GRB030131
  65. GRB 030131 optical observations
  66. GRB 030131 optical observations
  67. A long GRB detected by INTEGRAL
  68. GRB030115: 1.2 mm upper limits with MAMBO @ IRAM 30m
  69. Type Ic SN2003L (SN/GRB?) Radio Observations
  70. IPN triangulation of GRB030127 (annulus)
  71. GRB030115 submm upper limit
  72. IPN triangulation of GRB030119 (two large error boxes)
  73. GRB 030115: Further IR observations with IRSF/SIRIUS
  74. IPN triangulation of GRB030117 (two large error boxes)
  75. Publicizing GRB Discoveries - A Message from NASA HQ
  76. GRB 030115: Radio detection of IR candidate
  77. GRB 030115, simultaneous observations by BOOTES-1
  78. GRB 030115: IR observations with IRSF/SIRIUS
  79. IPN triangulation of GRB030115C (large error box)
  80. GRB030115: R-band counterpart of IR candidate
  81. GRB030115, afterglow candidate
  82. GRB 021211: R-band observations at late-time
  83. GRB030115: Optical Observations, Swiss Telescope at La Silla (ESO, Chile)
  84. IPN triangulation of GRB030115B (small error box)
  85. GRB 030115 : Possible IR counterpart
  86. GRB 030115: Radio Observations
  87. GRB030115 (=H2533): A Long GRB Localized by the HETE WXM and SXC
  88. Distribution of INTEGRAL SPI-ACS triggers for GRB bursts
  89. IPN triangulation of GRB030115B (annulus)
  90. ANNOUNCEMENT ON INTEGRAL GRB ALERTS
  91. Distribution of INTEGRAL SPI-ACS triggers
  92. GRB030115: R-band observations at Asiago
  93. GRB030115: TAROT optical observations
  94. GRB 021211: VLT spectrum
  95. GRB 030115: APO Optical Observations
  96. GRB 030115, no optical candidate
  97. GRB 030115, optical observations
  98. GRB 030115, optical candidate
  99. Possible GRB030113 seen by SPI ACS
  100. Probable GRB030112B seen by SPI ACS

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