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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"

37943 results found.

  1. GRB 030227: Optical observations
  2. GRB030226, BVRc observations
  3. Chandra detection of the X-ray afterglow of GRB 030226
  4. GRB 030226, further optical/NIR imaging
  5. GRB030227, optical observations
  6. GRB 030226: Ic Observations
  7. GRB030227: Kiso optical upper limit
  8. IPN triangulation of GRB030301 (annulus)
  9. IPN triangulation of GRB030228 (annulus)
  10. GRB030227, BVRcIc field photometry
  11. GRB030226, BVRcIc field calibration
  12. GRB 030227 optical afterglow
  13. 030302: NOT A GRB
  14. 030228: NOT A GRB
  15. GRB 030228, optical observations
  16. GRB 030226: Steep Decline
  17. GRB 030227: Confirmed Optical Afterglow (S1-A)
  18. GRB 030226: R band polarimetric observations
  19. GRB 030226: Optical observations
  20. GRB 030227: fading of candidate optical afterglow 'S1-A'
  21. GRB030227:Optical observations
  22. GRB 20030226: Upper limits from recent and historical observations
  23. GRB 030227, possible optical counterpart of XMM-Newton source
  24. GRB030227 - faint tentative OT candidate
  25. GRB 030226, optical observations
  26. GRB030227: Kiso optical observations
  27. GRB 030227: Kyoto optical observation
  28. GRB 030226, optical light curve
  29. GRB 030226 spectroscopy
  30. Possible break in the GRB 030226 light curve
  31. GRB 030226 : Predicted light curve
  32. IPN triangulation of GRB030225 (annulus)
  33. GRB 030226: Confirmed decay index
  34. GRB030226: ESI spectroscopy
  35. GRB030226 (=U10893): A Long GRB Localized by the HETE WXM and SXC
  36. GRB 030226 simultaneous optical observations
  37. Two absorption systems in GRB 030226
  38. GRB 030226, optical observations
  39. GRB 030226 Optical Spectra and R,I,z' Imaging
  40. GRB 030226, optical observations
  41. GRB 030226: Optical afterglow
  42. GRB 030217: Optical Observations at 4, 5, and 6 Days
  43. IPN triangulation of GRB030223 (annulus)
  44. IPN triangulation of GRB030220 (annulus)
  45. GRB: Non-Referencing of GCN Circulars.
  46. IPN triangulation of GRB030218 (annulus)
  47. IPN triangulation of GRB030217 (small error box)
  48. IPN triangulation of GRB030215C (annulus)
  49. IPN triangulation of GRB030217 (annulus)
  50. IPN triangulation of GRB030216 (annulus)
  51. IPN triangulation of GRB030215A and GRB030215B (annuli)
  52. GRB030115, WSRT radio observations - correction to GCN 1864
  53. GRB 030131: marginal optical detection
  54. GRB030115, WSRT radio observations
  55. IPN triangulation of GRB030206 (annulus)
  56. IPN triangulation of GRB030208 (annulus)
  57. GRB 030204: Optical Observations
  58. GRB030204 field photometry
  59. GRB020819: Kiso R and I band observations
  60. GRB 030204: Correction to GCN 1856
  61. GRB 030115: Optical Observations
  62. GRB 030204, optical observations
  63. IPN triangulation of GRB030204 (small error box)
  64. IPN triangulation of GRB030202 (annulus)
  65. GRB 030131, optical observations
  66. GRB030131: Kiso optical limit for corrected position
  67. GRB030131: Optical limits for corrected position
  68. GRB 030131: afterglow candidate
  69. GRB 030115, late-time optical observations
  70. GRB030131: corrected INTEGRAL position
  71. Type Ic SN2003L (SN/GRB?), optical spectrum
  72. GRB030131: Kiso Observations
  73. GRB 020819: Host galaxy at Radio Position
  74. IPN triangulation of GRB030131 - CORRECTION
  75. GRB 020819: afterglow candidate
  76. IPN triangulation of GRB030131
  77. GRB 030131 optical observations
  78. GRB 030131 optical observations
  79. A long GRB detected by INTEGRAL
  80. GRB030115: 1.2 mm upper limits with MAMBO @ IRAM 30m
  81. Type Ic SN2003L (SN/GRB?) Radio Observations
  82. IPN triangulation of GRB030127 (annulus)
  83. GRB030115 submm upper limit
  84. IPN triangulation of GRB030119 (two large error boxes)
  85. GRB 030115: Further IR observations with IRSF/SIRIUS
  86. IPN triangulation of GRB030117 (two large error boxes)
  87. Publicizing GRB Discoveries - A Message from NASA HQ
  88. GRB 030115: Radio detection of IR candidate
  89. GRB 030115, simultaneous observations by BOOTES-1
  90. GRB 030115: IR observations with IRSF/SIRIUS
  91. IPN triangulation of GRB030115C (large error box)
  92. GRB030115: R-band counterpart of IR candidate
  93. GRB030115, afterglow candidate
  94. GRB 021211: R-band observations at late-time
  95. GRB030115: Optical Observations, Swiss Telescope at La Silla (ESO, Chile)
  96. IPN triangulation of GRB030115B (small error box)
  97. GRB 030115 : Possible IR counterpart
  98. GRB 030115: Radio Observations
  99. GRB030115 (=H2533): A Long GRB Localized by the HETE WXM and SXC
  100. Distribution of INTEGRAL SPI-ACS triggers for GRB bursts

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