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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"
  1. Gemini IR Detection of AXP 1E 2259+586 Post-Burst
  2. SGR-like X-ray Bursts from AXP 1E 2259+586: follow-up
  3. AXP 1E2259+586: quasi-simultaneous optical observation
  4. AXP 1E2259+586 optical observations
  5. Fading Optical Source in the Field of GRB020531
  6. GRB 020531, INT+WFC deep optical upper limits
  7. SGR-like Bursts from the AXP 1E 2259+586
  8. GRB020405: polarimetric observations
  9. GRB 020531, simultaneous optical observations
  10. GRB 020604, optical observations
  11. GRB 020531/Candidate Redshift
  12. GRB020531: Detection of Candidate Host Galaxy
  13. GRB020531: Second epoch Chandra observations
  14. GRB020604, optical observations
  15. GRB020604, BVRcIc field photometry
  16. GRB020603, BVRcIc field observations
  17. GRB020531, BVRcIc field photometry
  18. GRB020531 Optical observations with TAROT
  19. GRB020531 Optical observations with TAROT
  20. GRB 020418, optical/near-IR observations
  21. GRB 020531, Radio Observations
  22. IPN triangulation of GRB020604
  23. GRB020531 Optical Observations
  24. GRB020531: Observations with the Chandra X-ray Observatory
  25. GRB 020603: Optical Observations
  26. GRB 020603, R-band observation
  27. Correction to IPN triangulation of GRB020603 (possible short/hard burst)
  28. GRB020531: Upper Limit for Detection of Two TAROT Sources
  29. GRB 020603: Optical observations
  30. IPN triangulation of GRB020603 (possible short/hard GRB)
  31. GRB 020531 optical observations with TAROT
  32. Refined IPN error box for GRB020531
  33. GRB020531, optical observations
  34. GRB020531: optical observations
  35. GRB020531, optical observation
  36. GRB020531(=H2042): Optical Observations
  37. IPN triangulation of the short, hard GRB020531 (=H2042)
  38. GRB020531(=H2042): Optical Observations
  39. GRB020531: Optical observations
  40. GRB020531(=H2042): A Short, Hard Burst Localized by HETE
  41. GRB 020525: Optical Observations
  42. GRB020525, optical observations
  43. IPN detection of possible bursts from SGR1806-20
  44. IPN triangulation of GRB020525
  45. XRF 020427: Sudden Ionospheric Disturbance (SID)
  46. HETE Observations of GX354-0 (= MXB1728-34, so-called "Slow
  47. XRF020427: Chandra Identification of a Likely X-ray Counterpart
  48. IPN triangulation of a burst from SGR1806-20
  49. GRB/XRF 020427, Radio Observations
  50. HST detection of the likely host galaxy of GRB 020124
  51. GRB020405 field photometry at ESO
  52. XRF020427: Chandra Observations and Candidate X-ray Counterparts
  53. GRB(XRF) 020427: X-ray afterglow with BeppoSAX
  54. GRB020321 : Optical observations.
  55. GRB020427 BeppoSAX NFI Observation
  56. XRF 020427
  57. GRB020331: Third Epoch and Revised Second Epoch Optical
  58. The end of BSAX GRB activities
  59. GRB 020410, Radio Observations
  60. GRB 020418: Optical observations
  61. GRB 020124: Optical observations
  62. GRB 020418: Optical observations
  63. IPN triangulation of GRB020418
  64. GRB020405: VLT observations of the OT environment
  65. GRB020410: BeppoSAX NFI observations refined analysis
  66. GRB 020409: Optical Observations
  67. Mars Odyssey joins the IPN
  68. IPN triangulation of GRB020413
  69. GRB 020409, 2-nd epoch optical observations at Terskol.
  70. GRB020405: predicted break
  71. GRB 020409: Optical observations
  72. GRB 020409, No Optical Detection to R = 22
  73. GRB020410: second BeppoSAX NFI observation
  74. GRB 020409: No Evidence for an Optical Afterglow
  75. GRB 020409, 2nd epoch optical observations
  76. GRB 020331 Kyoto observation on March 31
  77. GRB 020409
  78. GRB 020409 SARA Observations
  79. GRB "020411"
  80. GRB 020409, No Optical Detection to R = 20
  81. GRB020410: BeppoSAX NFI observation
  82. GRB 020409: Optical observations
  83. April 11 BeppoSAX event (GRB020411) is likely not a GRB
  84. GRB 020410, optical observations
  85. BeppoSAX ALERT: possible GRB020411
  86. GRB 020409, optical observations
  87. GRB 020409: Optical Observations
  88. GRB020406(?), optical observations
  89. GRB020410, optical observations
  90. BeppoSAX ALERT: possible GRB020410
  91. X-ray afterglow of GRB020321
  92. BeppoSAX GRB : GRB020409
  93. GRB020331: Confirmation of Afterglow Candidate with Magellan
  94. GRB020405: VLT optical observations and V band decay slope
  95. GRB020331 optical observations with RIMOTS
  96. GRB020124 optical observations with RIBOTS/RIMOTS
  97. GRB 020321: Candidate X-ray Counterparts
  98. ASM GRB candidate 020406 refined error box
  99. GRB 020405: Moderate-resolution spectroscopy
  100. GRB020331: Optical Observations of Afterglow Candidate

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