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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"

36146 results found.

  1. GRB030226, BVRc observations
  2. Chandra detection of the X-ray afterglow of GRB 030226
  3. GRB 030226, further optical/NIR imaging
  4. GRB030227, optical observations
  5. GRB 030226: Ic Observations
  6. GRB030227: Kiso optical upper limit
  7. IPN triangulation of GRB030301 (annulus)
  8. IPN triangulation of GRB030228 (annulus)
  9. GRB030227, BVRcIc field photometry
  10. GRB030226, BVRcIc field calibration
  11. GRB 030227 optical afterglow
  12. 030302: NOT A GRB
  13. 030228: NOT A GRB
  14. GRB 030228, optical observations
  15. GRB 030226: Steep Decline
  16. GRB 030227: Confirmed Optical Afterglow (S1-A)
  17. GRB 030226: R band polarimetric observations
  18. GRB 030226: Optical observations
  19. GRB 030227: fading of candidate optical afterglow 'S1-A'
  20. GRB030227:Optical observations
  21. GRB 20030226: Upper limits from recent and historical observations
  22. GRB 030227, possible optical counterpart of XMM-Newton source
  23. GRB030227 - faint tentative OT candidate
  24. GRB 030226, optical observations
  25. GRB030227: Kiso optical observations
  26. GRB 030227: Kyoto optical observation
  27. GRB 030226, optical light curve
  28. GRB 030226 spectroscopy
  29. Possible break in the GRB 030226 light curve
  30. GRB 030226 : Predicted light curve
  31. IPN triangulation of GRB030225 (annulus)
  32. GRB 030226: Confirmed decay index
  33. GRB030226: ESI spectroscopy
  34. GRB030226 (=U10893): A Long GRB Localized by the HETE WXM and SXC
  35. GRB 030226 simultaneous optical observations
  36. Two absorption systems in GRB 030226
  37. GRB 030226, optical observations
  38. GRB 030226 Optical Spectra and R,I,z' Imaging
  39. GRB 030226, optical observations
  40. GRB 030226: Optical afterglow
  41. GRB 030217: Optical Observations at 4, 5, and 6 Days
  42. IPN triangulation of GRB030223 (annulus)
  43. IPN triangulation of GRB030220 (annulus)
  44. GRB: Non-Referencing of GCN Circulars.
  45. IPN triangulation of GRB030218 (annulus)
  46. IPN triangulation of GRB030217 (small error box)
  47. IPN triangulation of GRB030215C (annulus)
  48. IPN triangulation of GRB030217 (annulus)
  49. IPN triangulation of GRB030216 (annulus)
  50. IPN triangulation of GRB030215A and GRB030215B (annuli)
  51. GRB030115, WSRT radio observations - correction to GCN 1864
  52. GRB 030131: marginal optical detection
  53. GRB030115, WSRT radio observations
  54. IPN triangulation of GRB030206 (annulus)
  55. IPN triangulation of GRB030208 (annulus)
  56. GRB 030204: Optical Observations
  57. GRB030204 field photometry
  58. GRB020819: Kiso R and I band observations
  59. GRB 030204: Correction to GCN 1856
  60. GRB 030115: Optical Observations
  61. GRB 030204, optical observations
  62. IPN triangulation of GRB030204 (small error box)
  63. IPN triangulation of GRB030202 (annulus)
  64. GRB 030131, optical observations
  65. GRB030131: Kiso optical limit for corrected position
  66. GRB030131: Optical limits for corrected position
  67. GRB 030131: afterglow candidate
  68. GRB 030115, late-time optical observations
  69. GRB030131: corrected INTEGRAL position
  70. Type Ic SN2003L (SN/GRB?), optical spectrum
  71. GRB030131: Kiso Observations
  72. GRB 020819: Host galaxy at Radio Position
  73. IPN triangulation of GRB030131 - CORRECTION
  74. GRB 020819: afterglow candidate
  75. IPN triangulation of GRB030131
  76. GRB 030131 optical observations
  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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