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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"

41677 results found.

  1. GRB 030226: Steep Decline
  2. GRB 030227: Confirmed Optical Afterglow (S1-A)
  3. GRB 030226: R band polarimetric observations
  4. GRB 030226: Optical observations
  5. GRB 030227: fading of candidate optical afterglow 'S1-A'
  6. GRB030227:Optical observations
  7. GRB 20030226: Upper limits from recent and historical observations
  8. GRB 030227, possible optical counterpart of XMM-Newton source
  9. GRB030227 - faint tentative OT candidate
  10. GRB 030226, optical observations
  11. XMM-Newton observation of GRB030227
  12. GRB030227: Kiso optical observations
  13. GRB 030227: Kyoto optical observation
  14. GRB 030226, optical light curve
  15. GRB 030226 spectroscopy
  16. GRB030227: refined INTEGRAL position
  17. GRB030227 localized by INTEGRAL
  18. Possible break in the GRB 030226 light curve
  19. GRB 030226 : Predicted light curve
  20. GRB030226: optical observation
  21. GRB 030226: Confirmed decay index
  22. GRB030226: ESI spectroscopy
  23. GRB 030226 simultaneous optical observations
  24. Two absorption systems in GRB 030226
  25. GRB 030226, optical observations
  26. GRB030226: optical observations and refined redshift
  27. GRB030226: Optical decay index
  28. GRB 030226 Optical Spectra and R,I,z' Imaging
  29. GRB 030226, optical observations
  30. GRB 030226: Optical afterglow
  31. GRB030226: Candidate optical afterglow
  32. GRB 030217: Optical Observations at 4, 5, and 6 Days
  33. GRB030217: optical observations
  34. IPN triangulation of GRB030217 (small error box)
  35. IPN triangulation of GRB030215A and GRB030215B (annuli)
  36. GRB030115, WSRT radio observations - correction to GCN 1864
  37. GRB 030131: marginal optical detection
  38. GRB030115, WSRT radio observations
  39. IPN triangulation of GRB030206 (annulus)
  40. GRB 030204: Optical Observations
  41. GRB030204 field photometry
  42. GRB020819: Kiso R and I band observations
  43. GRB030131: Candidate Optical Afterglow
  44. GRB 030115: Optical Observations
  45. GRB 030204, optical observations
  46. IPN triangulation of GRB030202 (annulus)
  47. GRB 030131, optical observations
  48. GRB030131: Kiso optical limit for corrected position
  49. GRB030131: Optical limits for corrected position
  50. GRB 030131: afterglow candidate
  51. GRB 030115, late-time optical observations
  52. GRB030131: corrected INTEGRAL position
  53. Type Ic SN2003L (SN/GRB?), optical spectrum
  54. GRB030131: Kiso Observations
  55. GRB 020819: Host galaxy at Radio Position
  56. IPN triangulation of GRB030131 - CORRECTION
  57. GRB 020819: afterglow candidate
  58. IPN triangulation of GRB030131
  59. GRB030131: Optical limit
  60. GRB 030131 optical observations
  61. GRB030131: refined position
  62. GRB 030131 optical observations
  63. A long GRB detected by INTEGRAL
  64. GRB030115: 1.2 mm upper limits with MAMBO @ IRAM 30m
  65. Type Ic SN2003L (SN/GRB?) Radio Observations
  66. GRB030115 submm upper limit
  67. GRB 030115: Further IR observations with IRSF/SIRIUS
  68. GRB 030115: Radio detection of IR candidate
  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. Distribution of INTEGRAL SPI-ACS triggers for GRB bursts
  79. Distribution of INTEGRAL SPI-ACS triggers
  80. GRB030115: R-band observations at Asiago
  81. GRB030115: TAROT optical observations
  82. GRB 021211: VLT spectrum
  83. GRB 030115: APO Optical Observations
  84. GRB 030115, no optical candidate
  85. GRB 030115, optical observations
  86. GRB 030115, optical candidate
  87. Information about where HETE will be pointing
  88. IPN triangulation of GRB030109 (annulus)
  89. IPN triangulation of GRB030105 (large error box)
  90. Coronas-F -Wind triangulation of GRB030102
  91. VLT spectroscopy of the probable host of GRB 021211
  92. GRB 021211: Probable Host and Underlying Supernova
  93. Probable GRB in INTEGRAL SPI-ACS
  94. IPN triangulation of GRB021223 (two large error boxes)
  95. GRB021211, radio observations
  96. GRB 021112: Evidence for Another Dark Optical Afterglow
  97. GRB 021219: OSN optical observations
  98. GRB021219: Radio Observations
  99. GRB021219, optical observations
  100. IPN triangulation of GRB021219

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