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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. GRB020813: Fading of Candidate OT
  2. GRB020813(=H2262): A Long, Bright Burst Localized by HETE in Near-Real Time
  3. GRB020813: Candidate Optical Afterglow
  4. GRB 020812 optical observation
  5. GRB020812(=H2257): A Long Burst Localized by HETE in Near-Real Time
  6. GRB 020715, optical observations
  7. GRB 020714, optical observations
  8. GRB020801: Imaging of Suggested OT Counterpart at the Magellan
  9. GRB020801: Candidate OT present in DSS
  10. HST Imaging of the Host of GRB 011121
  11. GRB020801, optical afterglow candidate
  12. Further refinement to IPN error box for GRB020531
  13. GRB020331: Late-time Optical Light Curve (re-submission)
  14. GRB020331: Late-time Optical Light Curve
  15. GRB 020405: HST observations reveal red bump
  16. IPN triangulation of GRB020714
  17. IPN triangulation of GRB020715 (=GRB150702)
  18. IPN triangulation of GRB020714
  19. IPN triangulation of GRB150702
  20. GRB 020410: Discovery of Probable OT by HST
  21. GRB 020124, HST observations of the fading afterglow
  22. IPN triangulation of GRB020708
  23. IPN triangulation of GRB020708
  24. IPN error box for GRB020706
  25. Correction to IPN error box for GRB020706
  26. IPN triangulation of GRB020706
  27. GRB 020705: Optical observations
  28. GRB 020625, optical observations
  29. GRB 020625: Optical observations
  30. GRB 020531: optical photometry of Chandra sources
  31. GRB020625 (=H2081): A Long Burst Localized by HETE
  32. HETE #2081: Optical observations
  33. The Probable Host Galaxy of GRB/XRF 020427
  34. GRB/XRF 020427, detection of an underlying system with the VLT
  35. Gemini IR Detection of AXP 1E 2259+586 Post-Burst
  36. SGR-like X-ray Bursts from AXP 1E 2259+586: follow-up
  37. AXP 1E2259+586: quasi-simultaneous optical observation
  38. AXP 1E2259+586 optical observations
  39. Fading Optical Source in the Field of GRB020531
  40. GRB 020531, INT+WFC deep optical upper limits
  41. SGR-like Bursts from the AXP 1E 2259+586
  42. GRB020405: polarimetric observations
  43. GRB 020531, simultaneous optical observations
  44. GRB 020604, optical observations
  45. GRB 020531/Candidate Redshift
  46. GRB020531: Detection of Candidate Host Galaxy
  47. GRB020531: Second epoch Chandra observations
  48. GRB020604, optical observations
  49. GRB020604, BVRcIc field photometry
  50. GRB020603, BVRcIc field observations
  51. GRB020531, BVRcIc field photometry
  52. GRB020531 Optical observations with TAROT
  53. GRB020531 Optical observations with TAROT
  54. GRB 020418, optical/near-IR observations
  55. GRB 020531, Radio Observations
  56. IPN triangulation of GRB020604
  57. GRB020531 Optical Observations
  58. GRB020531: Observations with the Chandra X-ray Observatory
  59. GRB 020603: Optical Observations
  60. GRB 020603, R-band observation
  61. Correction to IPN triangulation of GRB020603 (possible short/hard burst)
  62. GRB020531: Upper Limit for Detection of Two TAROT Sources
  63. GRB 020603: Optical observations
  64. IPN triangulation of GRB020603 (possible short/hard GRB)
  65. GRB 020531 optical observations with TAROT
  66. Refined IPN error box for GRB020531
  67. GRB020531, optical observations
  68. GRB020531: optical observations
  69. GRB020531, optical observation
  70. GRB020531(=H2042): Optical Observations
  71. IPN triangulation of the short, hard GRB020531 (=H2042)
  72. GRB020531(=H2042): Optical Observations
  73. GRB020531: Optical observations
  74. GRB020531(=H2042): A Short, Hard Burst Localized by HETE
  75. GRB 020525: Optical Observations
  76. GRB020525, optical observations
  77. IPN detection of possible bursts from SGR1806-20
  78. IPN triangulation of GRB020525
  79. XRF 020427: Sudden Ionospheric Disturbance (SID)
  80. HETE Observations of GX354-0 (= MXB1728-34, so-called "Slow
  81. XRF020427: Chandra Identification of a Likely X-ray Counterpart
  82. IPN triangulation of a burst from SGR1806-20
  83. GRB/XRF 020427, Radio Observations
  84. HST detection of the likely host galaxy of GRB 020124
  85. GRB020405 field photometry at ESO
  86. XRF020427: Chandra Observations and Candidate X-ray Counterparts
  87. GRB(XRF) 020427: X-ray afterglow with BeppoSAX
  88. GRB020321 : Optical observations.
  89. GRB020427 BeppoSAX NFI Observation
  90. XRF 020427
  91. GRB020331: Third Epoch and Revised Second Epoch Optical
  92. The end of BSAX GRB activities
  93. GRB 020410, Radio Observations
  94. GRB 020418: Optical observations
  95. GRB 020124: Optical observations
  96. GRB 020418: Optical observations
  97. IPN triangulation of GRB020418
  98. GRB020405: VLT observations of the OT environment
  99. GRB020410: BeppoSAX NFI observations refined analysis
  100. GRB 020409: Optical Observations

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