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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"

32504 results found.

  1. GRB030226: Optical observations at Asiago
  2. IPN triangulation of GRB030306 (two small error boxes)
  3. GRB 030226: Optical observations
  4. GRB030226: Analysis of Chandra data
  5. GRB 030227: Optical observations
  6. GRB030226, BVRc observations
  7. Chandra detection of the X-ray afterglow of GRB 030226
  8. GRB 030226, further optical/NIR imaging
  9. GRB 030226: Ic Observations
  10. GRB030227: Kiso optical upper limit
  11. GRB030227, BVRcIc field photometry
  12. GRB030226, BVRcIc field calibration
  13. GRB 030227 optical afterglow
  14. GRB 030226: Steep Decline
  15. GRB 030227: Confirmed Optical Afterglow (S1-A)
  16. GRB 030226: R band polarimetric observations
  17. GRB 030226: Optical observations
  18. GRB 030227: fading of candidate optical afterglow 'S1-A'
  19. GRB030227:Optical observations
  20. GRB 20030226: Upper limits from recent and historical observations
  21. GRB 030227, possible optical counterpart of XMM-Newton source
  22. GRB030227 - faint tentative OT candidate
  23. GRB 030226, optical observations
  24. XMM-Newton observation of GRB030227
  25. GRB 030227: Kyoto optical observation
  26. GRB 030226, optical light curve
  27. GRB 030226 spectroscopy
  28. Possible break in the GRB 030226 light curve
  29. GRB030226: optical observation
  30. GRB 030226: Confirmed decay index
  31. GRB030226: ESI spectroscopy
  32. GRB030226 (=U10893): A Long GRB Localized by the HETE WXM and SXC
  33. Two absorption systems in GRB 030226
  34. GRB 030226, optical observations
  35. GRB030226: optical observations and refined redshift
  36. GRB 030226, optical observations
  37. GRB 030226: Optical afterglow
  38. GRB 030217: Optical Observations at 4, 5, and 6 Days
  39. GRB: Non-Referencing of GCN Circulars.
  40. GRB030217: optical observations
  41. IPN triangulation of GRB030217 (small error box)
  42. GRB030115, WSRT radio observations - correction to GCN 1864
  43. GRB 030131: marginal optical detection
  44. GCN/INTEGRAL Mistake Fixed
  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. GRB030131: Candidate Optical Afterglow
  50. GRB 030115: Optical Observations
  51. GRB 030204, optical observations
  52. GRB 030131, optical observations
  53. GRB030131: Kiso optical limit for corrected position
  54. GRB030131: Optical limits for corrected position
  55. GRB 030131: afterglow candidate
  56. GRB 030115, late-time optical observations
  57. Type Ic SN2003L (SN/GRB?), optical spectrum
  58. GRB 020819: Host galaxy at Radio Position
  59. IPN triangulation of GRB030131 - CORRECTION
  60. IPN triangulation of GRB030131
  61. GRB030131: Optical limit
  62. GRB 030131 optical observations
  63. GRB030131: refined position
  64. GRB 030131 optical observations
  65. GRB030115: 1.2 mm upper limits with MAMBO @ IRAM 30m
  66. GRB030115 submm upper limit
  67. GRB 030115: Further IR observations with IRSF/SIRIUS
  68. Publicizing GRB Discoveries - A Message from NASA HQ
  69. GRB 030115, simultaneous observations by BOOTES-1
  70. GRB 030115: IR observations with IRSF/SIRIUS
  71. GRB030115: R-band counterpart of IR candidate
  72. GRB030115, afterglow candidate
  73. GRB 021211: R-band observations at late-time
  74. GRB030115: Optical Observations, Swiss Telescope at La Silla (ESO, Chile)
  75. IPN triangulation of GRB030115B (small error box)
  76. GRB 030115 : Possible IR counterpart
  77. GRB 030115: Radio Observations
  78. GRB030115 (=H2533): A Long GRB Localized by the HETE WXM and SXC
  79. Distribution of INTEGRAL SPI-ACS triggers for GRB bursts
  80. ANNOUNCEMENT ON INTEGRAL GRB ALERTS
  81. Distribution of INTEGRAL SPI-ACS triggers
  82. GRB030115: TAROT optical observations
  83. GRB 021211: VLT spectrum
  84. GRB 030115: APO Optical Observations
  85. GRB 030115, no optical candidate
  86. GRB 030115, optical observations
  87. GRB 030115, optical candidate
  88. IPN triangulation of GRB030109 (annulus)
  89. IPN triangulation of GRB030105 (large error box)
  90. IPN triangulation of GRB030102B (refined localization - portion of annulus)
  91. Coronas-F -Wind triangulation of GRB030102
  92. IPN triangulation of GRB030102 (annulus)
  93. VLT spectroscopy of the probable host of GRB 021211
  94. GRB021226
  95. GRB 021211: Probable Host and Underlying Supernova
  96. GRB 021226 registration by Helicon/Coronas-F
  97. GRB 021112: Evidence for Another Dark Optical Afterglow
  98. GRB 021219: OSN optical observations
  99. GRB021219: Radio Observations
  100. GRB021219, optical observations

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