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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"

16161 results found.

  1. GRB 030226: Ic Observations
  2. GRB030227: Kiso optical upper limit
  3. GRB030227, BVRcIc field photometry
  4. GRB030226, BVRcIc field calibration
  5. GRB 030227 optical afterglow
  6. GRB 030228, optical observations
  7. GRB 030226: Steep Decline
  8. GRB 030227: Confirmed Optical Afterglow (S1-A)
  9. GRB 030226: R band polarimetric observations
  10. GRB 030226: Optical observations
  11. GRB 030227: fading of candidate optical afterglow 'S1-A'
  12. GRB030227:Optical observations
  13. GRB 20030226: Upper limits from recent and historical observations
  14. GRB 030227, possible optical counterpart of XMM-Newton source
  15. GRB030227 - faint tentative OT candidate
  16. GRB 030226, optical observations
  17. GRB030227: Kiso optical observations
  18. GRB 030227: Kyoto optical observation
  19. GRB 030226, optical light curve
  20. GRB 030226 spectroscopy
  21. GRB 030226 : Predicted light curve
  22. GRB030226: optical observation
  23. GRB030226 (=U10893): A Long GRB Localized by the HETE WXM and SXC
  24. GRB 030226 simultaneous optical observations
  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. GRB 030131: marginal optical detection
  35. GRB 030204: Optical Observations
  36. GRB030131: Candidate Optical Afterglow
  37. GRB 030115: Optical Observations
  38. GRB 030204, optical observations
  39. GRB 030131, optical observations
  40. GRB030131: Kiso optical limit for corrected position
  41. GRB030131: Optical limits for corrected position
  42. GRB 030115, late-time optical observations
  43. Type Ic SN2003L (SN/GRB?), optical spectrum
  44. GRB 020819: Host galaxy at Radio Position
  45. GRB 020819: afterglow candidate
  46. GRB030131: Optical limit
  47. GRB 030131 optical observations
  48. GRB 030131 optical observations
  49. Type Ic SN2003L (SN/GRB?) Radio Observations
  50. GRB 030115, simultaneous observations by BOOTES-1
  51. GRB030115: R-band counterpart of IR candidate
  52. GRB 021211: R-band observations at late-time
  53. GRB030115: Optical Observations, Swiss Telescope at La Silla (ESO, Chile)
  54. GRB030115 (=H2533): A Long GRB Localized by the HETE WXM and SXC
  55. GRB030115: TAROT optical observations
  56. GRB 030115: APO Optical Observations
  57. GRB 030115, no optical candidate
  58. GRB 030115, optical observations
  59. GRB 030115, optical candidate
  60. GRB 021211: Probable Host and Underlying Supernova
  61. GRB021211, radio observations
  62. GRB 021112: Evidence for Another Dark Optical Afterglow
  63. GRB 021219: OSN optical observations
  64. GRB021219, optical observations
  65. GRB021219, optical observation by MASTER
  66. GRB021211: APO optical observations
  67. IPN detection of continued activity from SGR1806-20
  68. XRF 020903 : HST observations
  69. GRB 021201: Optical Observations
  70. GRB 021211, optical observations
  71. GRB 021211: CTIO observations
  72. GRB021211: Measurement of Early Time Afterglow
  73. GRB021211, BVRI field photometry
  74. GRB021211: Optical observations in CrAO
  75. GRB 021211, optical observations
  76. GRB 021211: Optical Observations
  77. GRB021211: Kiso Observations
  78. GRB021204: Kiso Observations
  79. GRB 021201, optical observations
  80. GRB 021211: Radio Observations
  81. GRB021211: Optical observations
  82. GRB 021201 (short/hard), NOT observations
  83. GRB021211 - Upper limits from recent and historical observations
  84. GRB021211 (=H2493): A Bright, Long GRB Localized by HETE-2 in Near-Real Time
  85. HETE 2493: Optical observations
  86. HETE 2493: Optical observations
  87. HETE 2493: Optical candidate
  88. GRB 021204: Optical Observations at RIKEN
  89. GRB 021201: Optical Observations
  90. GRB 021201: BOOTES simultaneous optical observations
  91. GRB021004, late time optical observations
  92. IPN detection of continued SGR1900+14 activity
  93. GRB021113, SPI ACS observation
  94. GRB021113: optical observations at Bisei
  95. GRB 021113: Evidence for a Dark Optical Afterglow
  96. GRB 021112: Variable Source in R-band search
  97. GRB021112: Optical Observations
  98. GRB 021113: Optical observations
  99. GRB 021112: RAPTOR Observations
  100. GRB 021113: Optical Observations

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