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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. Swift UVOT upper limits of GRB071112B
  2. GRB 071112C: VLT redshift
  3. GRB 071112B: Magellan i-band imaging
  4. GRB 071112B: Gemini Optical Imaging (Correction)
  5. GRB 071112B: Gemini Optical Imaging
  6. GRB 071112B: Swift-XRT preliminary analysis
  7. GRB 071112B, Swift-BAT partial refined analysis of the SHB
  8. GRB071112C: NOT observations
  9. GRB 071112C: Palomar Pre-Imaging
  10. Swift-BAT trigger 296491 is not a GRB
  11. GRB 071112C : Lulin R-band observation
  12. GRB 071112C: RTT150 optical observations
  13. GRB 071112C: TAROT Calern observatory optical observations
  14. Swift XRT follow-up observations of GRB071028B
  15. GRB071112C Xinglong_TNT_and_EST_afterglow observations
  16. GRB 071112C: Optical and NIR afterglows observed with KANATA
  17. GRB 071112C: ROTSE-III Confirmation of Optical Counterpart
  18. GRB 071112B: ROTSE-III Rapid Optical Limits
  19. GRB 071112C: Swift detection of a burst with an optical counterpart
  20. GRB 071112B: Swift detection of a short hard burst
  21. GRB 071112: Swift detection of a possible burst
  22. GRB071109: Super-LOTIS observations
  23. VLA IInd observation of INTEGRAL burst GRB 071109
  24. Swift/UVOT initial analysis of GRB071109
  25. GRB 071109: further Swift-XRT analysis
  26. GRB 071109: TAROT Calern observatory optical observations
  27. No radio detection at Swift-XRT position
  28. GRB 071109: Swift-XRT possible X-ray counterpart
  29. VLA prompt radio detection of the INTEGRAL burst 071109
  30. GRB 071109: IBIS refined analysis
  31. GRB 071109: BOOTES-2 prompt optical observations
  32. GRB 071109: A long GRB detected by INTEGRAL
  33. GRB 071104: Swift-XRT Team Refined Analysis
  34. GRB 071104: Possible Swift UVOT Afterglow Candidate
  35. GRB 071104: Swift-XRT position
  36. GRB 071104: Gamma Ray Burst Localization by SuperAGILE
  37. GRB071010b: optical observation
  38. Swift XRT and UVOT observations of GRB071028B
  39. GRB 071101, Swift-BAT refined analysis
  40. GRB 071101: Swift-XRT Team refined analysis
  41. GRB071101: Optical and NIR upper limits by KANATA
  42. GRB0711101: Two new source from Xinglong TNT observation
  43. GRB 071101: TAROT Calern observatory optical observations
  44. GRB 071101: Swift XRT position
  45. GRB071101 LOAO B,V,R,I observation
  46. GRB 071101: BOOTES-2 prompt optical observations
  47. GRB 071101: a nearby galaxy
  48. GRB 071101: Swift detection of a burst
  49. GRB 071031, Swift-BAT refined analysis
  50. GRB 071031: Swift/UVOT detection of afterglow
  51. GRB 071031: Swift-XRT Team refined analysis
  52. GRB 071020: MITSuME Akeno optical observations
  53. GRB 071031: REM NIR and Optical observation
  54. GRB 071031, SMARTS afterglow observations
  55. GRB 071031: VLT high-resolution spectroscopy
  56. GRB071031: Rapid PROMPT Detections
  57. GRB 071031: GROND detection in all bands
  58. GRB 071031: Swift detection of a burst with an optical counterpart
  59. GRB 071028B Swift-BAT detection of a burst
  60. GRB071025: Optical+NIR observations
  61. GRB 071028: SARA observations of variable source
  62. Swift UVOT upper limits to GRB071028
  63. GRB071028: Xinglong EST V-band upper limit
  64. GRB 071028: Swift-XRT Team refined analysis
  65. GRB 071028, Swift-BAT refined analysis
  66. GRB 071028: Swift detection of a burst
  67. GRB 071025: Kuiper Telescope Optical Observations
  68. GRB 071003: Infrared Photometry with Keck Adaptive Optics
  69. GRB 071018: Revised BAT position
  70. GRB 071025A: RAPTOR Observations of Complex Early Optical Behavior
  71. GRB071021: MARGE Optical Limits
  72. GRB071020, optical upper limit
  73. GRB 071025: SARA VRI upper limits
  74. GRB 071025 Milagro GeV/TeV Observations
  75. GRB 071025: SQIID JHK photometry
  76. GRB 071025A: Complex Early-Time IR Behavior, Simultaneous with Gamma- and X-rays
  77. GRB071025: Optical Pre-imaging from Palomar
  78. Swift UVOT upper limits
  79. GRB071025: Xinglong TNT I-band upper limit
  80. GRB 071025: Swift-XRT Team refined analysis
  81. GRB 060602A: host redshift
  82. GRB 071025, Swift-BAT refined analysis
  83. GRB 071025: Early Super-LOTIS Observations
  84. GRB 071025: R/I-band update
  85. GRB071021 : CFHT Ks-band observation
  86. GRB 071025: ROTSE-III Refined Analysis
  87. GRB 071025: I-detection, R-dropout?
  88. GRB 071025: Swift XRT refined position
  89. GRB 071025a: PAIRITEL observations
  90. GRB071025: REM NIR afterglow
  91. GRB 071025: ROTSE-III Detection of Optical Counterpart
  92. GRB 071025: Swift detection of a burst
  93. GRB 071021: R-band detection and analysis
  94. GRB 071020: BTA spectroscopy
  95. GRB071021: Optical+NIR observations
  96. Possible radio detection of GRB 071021 with the VLA
  97. Optical observations of GRB 071020
  98. GRB 071021: (Relatively shallow) IR non-detections; motivation for optical spectroscopy
  99. GRB 071020: SARA observations
  100. Radio detection of GRB 071020 with the VLA

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