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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"

36143 results found.

  1. GRB030227, optical observations
  2. GRB 030226: Ic Observations
  3. GRB030227: Kiso optical upper limit
  4. IPN triangulation of GRB030301 (annulus)
  5. IPN triangulation of GRB030228 (annulus)
  6. GRB030227, BVRcIc field photometry
  7. GRB030226, BVRcIc field calibration
  8. GRB 030227 optical afterglow
  9. 030302: NOT A GRB
  10. 030228: NOT A GRB
  11. GRB 030228, optical observations
  12. GRB 030226: Steep Decline
  13. GRB 030227: Confirmed Optical Afterglow (S1-A)
  14. GRB 030226: R band polarimetric observations
  15. GRB 030226: Optical observations
  16. GRB 030227: fading of candidate optical afterglow 'S1-A'
  17. GRB030227:Optical observations
  18. GRB 20030226: Upper limits from recent and historical observations
  19. GRB 030227, possible optical counterpart of XMM-Newton source
  20. GRB030227 - faint tentative OT candidate
  21. GRB 030226, optical observations
  22. GRB030227: Kiso optical observations
  23. GRB 030227: Kyoto optical observation
  24. GRB 030226, optical light curve
  25. GRB 030226 spectroscopy
  26. Possible break in the GRB 030226 light curve
  27. GRB 030226 : Predicted light curve
  28. IPN triangulation of GRB030225 (annulus)
  29. GRB 030226: Confirmed decay index
  30. GRB030226: ESI spectroscopy
  31. GRB030226 (=U10893): A Long GRB Localized by the HETE WXM and SXC
  32. GRB 030226 simultaneous optical observations
  33. Two absorption systems in GRB 030226
  34. GRB 030226, optical observations
  35. GRB 030226 Optical Spectra and R,I,z' Imaging
  36. GRB 030226, optical observations
  37. GRB 030226: Optical afterglow
  38. GRB 030217: Optical Observations at 4, 5, and 6 Days
  39. IPN triangulation of GRB030223 (annulus)
  40. IPN triangulation of GRB030220 (annulus)
  41. GRB: Non-Referencing of GCN Circulars.
  42. IPN triangulation of GRB030218 (annulus)
  43. IPN triangulation of GRB030217 (small error box)
  44. IPN triangulation of GRB030215C (annulus)
  45. IPN triangulation of GRB030217 (annulus)
  46. IPN triangulation of GRB030216 (annulus)
  47. IPN triangulation of GRB030215A and GRB030215B (annuli)
  48. GRB030115, WSRT radio observations - correction to GCN 1864
  49. GRB 030131: marginal optical detection
  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. GRB 030115: Optical Observations
  58. GRB 030204, optical observations
  59. IPN triangulation of GRB030204 (small error box)
  60. IPN triangulation of GRB030202 (annulus)
  61. GRB 030131, optical observations
  62. GRB030131: Kiso optical limit for corrected position
  63. GRB030131: Optical limits for corrected position
  64. GRB 030131: afterglow candidate
  65. GRB 030115, late-time optical observations
  66. GRB030131: corrected INTEGRAL position
  67. Type Ic SN2003L (SN/GRB?), optical spectrum
  68. GRB030131: Kiso Observations
  69. GRB 020819: Host galaxy at Radio Position
  70. IPN triangulation of GRB030131 - CORRECTION
  71. GRB 020819: afterglow candidate
  72. IPN triangulation of GRB030131
  73. GRB 030131 optical observations
  74. GRB 030131 optical observations
  75. A long GRB detected by INTEGRAL
  76. GRB030115: 1.2 mm upper limits with MAMBO @ IRAM 30m
  77. Type Ic SN2003L (SN/GRB?) Radio Observations
  78. IPN triangulation of GRB030127 (annulus)
  79. GRB030115 submm upper limit
  80. IPN triangulation of GRB030119 (two large error boxes)
  81. GRB 030115: Further IR observations with IRSF/SIRIUS
  82. IPN triangulation of GRB030117 (two large error boxes)
  83. Publicizing GRB Discoveries - A Message from NASA HQ
  84. GRB 030115: Radio detection of IR candidate
  85. GRB 030115, simultaneous observations by BOOTES-1
  86. GRB 030115: IR observations with IRSF/SIRIUS
  87. IPN triangulation of GRB030115C (large error box)
  88. GRB030115: R-band counterpart of IR candidate
  89. GRB030115, afterglow candidate
  90. GRB 021211: R-band observations at late-time
  91. GRB030115: Optical Observations, Swiss Telescope at La Silla (ESO, Chile)
  92. IPN triangulation of GRB030115B (small error box)
  93. GRB 030115 : Possible IR counterpart
  94. GRB 030115: Radio Observations
  95. GRB030115 (=H2533): A Long GRB Localized by the HETE WXM and SXC
  96. Distribution of INTEGRAL SPI-ACS triggers for GRB bursts
  97. IPN triangulation of GRB030115B (annulus)
  98. ANNOUNCEMENT ON INTEGRAL GRB ALERTS
  99. Distribution of INTEGRAL SPI-ACS triggers
  100. GRB030115: R-band observations at Asiago

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