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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. Spectropolarimetry of GRB 020813
  2. GRB 020813 Afterglow Observations; Possible break
  3. GRB 020813: Absorption redshift
  4. GRB 020813 multiband optical observations
  5. GRB020813: optical afterglow
  6. GRB020813: Fading of Candidate OT
  7. GRB020813(=H2262): A Long, Bright Burst Localized by HETE in Near-Real Time
  8. GRB020813: Candidate Optical Afterglow
  9. GRB 020812 optical observation
  10. GRB020812(=H2257): A Long Burst Localized by HETE in Near-Real Time
  11. GRB 020715, optical observations
  12. GRB 020714, optical observations
  13. GRB020801: Imaging of Suggested OT Counterpart at the Magellan
  14. GRB020801: Candidate OT present in DSS
  15. HST Imaging of the Host of GRB 011121
  16. GRB020801, optical afterglow candidate
  17. Further refinement to IPN error box for GRB020531
  18. GRB020331: Late-time Optical Light Curve (re-submission)
  19. GRB020331: Late-time Optical Light Curve
  20. GRB 020405: HST observations reveal red bump
  21. IPN triangulation of GRB020714
  22. IPN triangulation of GRB020715 (=GRB150702)
  23. IPN triangulation of GRB020714
  24. IPN triangulation of GRB150702
  25. GRB 020410: Discovery of Probable OT by HST
  26. GRB 020124, HST observations of the fading afterglow
  27. IPN triangulation of GRB020708
  28. IPN triangulation of GRB020708
  29. IPN error box for GRB020706
  30. Correction to IPN error box for GRB020706
  31. IPN triangulation of GRB020706
  32. GRB 020705: Optical observations
  33. GRB 020625, optical observations
  34. GRB 020625: Optical observations
  35. GRB 020531: optical photometry of Chandra sources
  36. GRB020625 (=H2081): A Long Burst Localized by HETE
  37. HETE #2081: Optical observations
  38. The Probable Host Galaxy of GRB/XRF 020427
  39. GRB/XRF 020427, detection of an underlying system with the VLT
  40. Gemini IR Detection of AXP 1E 2259+586 Post-Burst
  41. SGR-like X-ray Bursts from AXP 1E 2259+586: follow-up
  42. AXP 1E2259+586: quasi-simultaneous optical observation
  43. AXP 1E2259+586 optical observations
  44. Fading Optical Source in the Field of GRB020531
  45. GRB 020531, INT+WFC deep optical upper limits
  46. SGR-like Bursts from the AXP 1E 2259+586
  47. GRB020405: polarimetric observations
  48. GRB 020531, simultaneous optical observations
  49. GRB 020604, optical observations
  50. GRB 020531/Candidate Redshift
  51. GRB020531: Detection of Candidate Host Galaxy
  52. GRB020531: Second epoch Chandra observations
  53. GRB020604, optical observations
  54. GRB020604, BVRcIc field photometry
  55. GRB020603, BVRcIc field observations
  56. GRB020531, BVRcIc field photometry
  57. GRB020531 Optical observations with TAROT
  58. GRB020531 Optical observations with TAROT
  59. GRB 020418, optical/near-IR observations
  60. GRB 020531, Radio Observations
  61. IPN triangulation of GRB020604
  62. GRB020531 Optical Observations
  63. GRB020531: Observations with the Chandra X-ray Observatory
  64. GRB 020603: Optical Observations
  65. GRB 020603, R-band observation
  66. Correction to IPN triangulation of GRB020603 (possible short/hard burst)
  67. GRB020531: Upper Limit for Detection of Two TAROT Sources
  68. GRB 020603: Optical observations
  69. IPN triangulation of GRB020603 (possible short/hard GRB)
  70. GRB 020531 optical observations with TAROT
  71. Refined IPN error box for GRB020531
  72. GRB020531, optical observations
  73. GRB020531: optical observations
  74. GRB020531, optical observation
  75. GRB020531(=H2042): Optical Observations
  76. IPN triangulation of the short, hard GRB020531 (=H2042)
  77. GRB020531(=H2042): Optical Observations
  78. GRB020531: Optical observations
  79. GRB020531(=H2042): A Short, Hard Burst Localized by HETE
  80. GRB 020525: Optical Observations
  81. GRB020525, optical observations
  82. IPN detection of possible bursts from SGR1806-20
  83. IPN triangulation of GRB020525
  84. XRF 020427: Sudden Ionospheric Disturbance (SID)
  85. HETE Observations of GX354-0 (= MXB1728-34, so-called "Slow
  86. XRF020427: Chandra Identification of a Likely X-ray Counterpart
  87. IPN triangulation of a burst from SGR1806-20
  88. GRB/XRF 020427, Radio Observations
  89. HST detection of the likely host galaxy of GRB 020124
  90. GRB020405 field photometry at ESO
  91. XRF020427: Chandra Observations and Candidate X-ray Counterparts
  92. GRB(XRF) 020427: X-ray afterglow with BeppoSAX
  93. GRB020321 : Optical observations.
  94. GRB020427 BeppoSAX NFI Observation
  95. XRF 020427
  96. GRB020331: Third Epoch and Revised Second Epoch Optical
  97. The end of BSAX GRB activities
  98. GRB 020410, Radio Observations
  99. GRB 020418: Optical observations
  100. GRB 020124: Optical observations

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