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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"

44615 results found.

  1. 030228: NOT A GRB
  2. GRB 030228, optical observations
  3. GRB 030226: Steep Decline
  4. GRB 030227: Confirmed Optical Afterglow (S1-A)
  5. GRB 030226: R band polarimetric observations
  6. GRB 030226: Optical observations
  7. GRB 030227: fading of candidate optical afterglow 'S1-A'
  8. GRB030227:Optical observations
  9. GRB 20030226: Upper limits from recent and historical observations
  10. GRB 030227, possible optical counterpart of XMM-Newton source
  11. GRB030227 - faint tentative OT candidate
  12. GRB 030226, optical observations
  13. XMM-Newton observation of GRB030227
  14. GRB030227: Kiso optical observations
  15. GRB 030227: Kyoto optical observation
  16. GRB 030226, optical light curve
  17. GRB 030226 spectroscopy
  18. GRB030227: refined INTEGRAL position
  19. GRB030227 localized by INTEGRAL
  20. Possible break in the GRB 030226 light curve
  21. GRB 030226 : Predicted light curve
  22. GRB030226: optical observation
  23. IPN triangulation of GRB030225 (annulus)
  24. GRB 030226: Confirmed decay index
  25. GRB030226: ESI spectroscopy
  26. GRB030226 (=U10893): A Long GRB Localized by the HETE WXM and SXC
  27. GRB 030226 simultaneous optical observations
  28. Two absorption systems in GRB 030226
  29. GRB 030226, optical observations
  30. GRB030226: optical observations and refined redshift
  31. GRB030226: Optical decay index
  32. GRB 030226 Optical Spectra and R,I,z' Imaging
  33. GRB 030226, optical observations
  34. GRB 030226: Optical afterglow
  35. GRB030226: Candidate optical afterglow
  36. GRB 030217: Optical Observations at 4, 5, and 6 Days
  37. IPN triangulation of GRB030223 (annulus)
  38. IPN triangulation of GRB030220 (annulus)
  39. GRB: Non-Referencing of GCN Circulars.
  40. IPN triangulation of GRB030218 (annulus)
  41. GRB030217: optical observations
  42. IPN triangulation of GRB030217 (small error box)
  43. IPN triangulation of GRB030215C (annulus)
  44. IPN triangulation of GRB030217 (annulus)
  45. IPN triangulation of GRB030216 (annulus)
  46. IPN triangulation of GRB030215A and GRB030215B (annuli)
  47. GRB030115, WSRT radio observations - correction to GCN 1864
  48. GRB 030131: marginal optical detection
  49. GCN/INTEGRAL Mistake Fixed
  50. GRB030115, WSRT radio observations
  51. IPN triangulation of GRB030206 (annulus)
  52. IPN triangulation of GRB030208 (annulus)
  53. GRB 030204: Optical Observations
  54. GRB030204 field photometry
  55. GRB020819: Kiso R and I band observations
  56. GRB 030204: Correction to GCN 1856
  57. GRB030131: Candidate Optical Afterglow
  58. GRB 030115: Optical Observations
  59. GRB 030204, optical observations
  60. IPN triangulation of GRB030204 (small error box)
  61. IPN triangulation of GRB030202 (annulus)
  62. GRB 030131, optical observations
  63. GRB030131: Kiso optical limit for corrected position
  64. GRB030131: Optical limits for corrected position
  65. GRB 030131: afterglow candidate
  66. GRB 030115, late-time optical observations
  67. GRB030131: corrected INTEGRAL position
  68. Type Ic SN2003L (SN/GRB?), optical spectrum
  69. GRB030131: Kiso Observations
  70. GRB 020819: Host galaxy at Radio Position
  71. IPN triangulation of GRB030131 - CORRECTION
  72. GRB 020819: afterglow candidate
  73. IPN triangulation of GRB030131
  74. GRB030131: Optical limit
  75. GRB 030131 optical observations
  76. GRB030131: refined position
  77. GRB 030131 optical observations
  78. A long GRB detected by INTEGRAL
  79. GRB030115: 1.2 mm upper limits with MAMBO @ IRAM 30m
  80. Type Ic SN2003L (SN/GRB?) Radio Observations
  81. IPN triangulation of GRB030127 (annulus)
  82. GRB030115 submm upper limit
  83. IPN triangulation of GRB030119 (two large error boxes)
  84. GRB 030115: Further IR observations with IRSF/SIRIUS
  85. IPN triangulation of GRB030117 (two large error boxes)
  86. Publicizing GRB Discoveries - A Message from NASA HQ
  87. GRB 030115: Radio detection of IR candidate
  88. GRB 030115, simultaneous observations by BOOTES-1
  89. GRB 030115: IR observations with IRSF/SIRIUS
  90. IPN triangulation of GRB030115C (large error box)
  91. GRB030115: R-band counterpart of IR candidate
  92. GRB030115, afterglow candidate
  93. GRB 021211: R-band observations at late-time
  94. GRB030115: Optical Observations, Swiss Telescope at La Silla (ESO, Chile)
  95. IPN triangulation of GRB030115B (small error box)
  96. GRB 030115 : Possible IR counterpart
  97. GRB 030115: Radio Observations
  98. GRB030115 (=H2533): A Long GRB Localized by the HETE WXM and SXC
  99. Distribution of INTEGRAL SPI-ACS triggers for GRB bursts
  100. IPN triangulation of GRB030115B (annulus)

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