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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. GRB 071112C : Lulin R-band observation
  2. GRB 071112C: RTT150 optical observations
  3. GRB 071112C: TAROT Calern observatory optical observations
  4. Swift XRT follow-up observations of GRB071028B
  5. GRB071112C Xinglong_TNT_and_EST_afterglow observations
  6. GRB 071112C: Optical and NIR afterglows observed with KANATA
  7. GRB 071112C: ROTSE-III Confirmation of Optical Counterpart
  8. GRB 071112B: ROTSE-III Rapid Optical Limits
  9. GRB 071112C: Swift detection of a burst with an optical counterpart
  10. GRB 071112B: Swift detection of a short hard burst
  11. GRB 071112: Swift detection of a possible burst
  12. GRB071109: Super-LOTIS observations
  13. VLA IInd observation of INTEGRAL burst GRB 071109
  14. Swift/UVOT initial analysis of GRB071109
  15. GRB 071109: further Swift-XRT analysis
  16. GRB 071109: TAROT Calern observatory optical observations
  17. No radio detection at Swift-XRT position
  18. GRB 071109: Swift-XRT possible X-ray counterpart
  19. VLA prompt radio detection of the INTEGRAL burst 071109
  20. GRB 071109: IBIS refined analysis
  21. GRB 071109: BOOTES-2 prompt optical observations
  22. GRB 071109: A long GRB detected by INTEGRAL
  23. GRB 071104: Swift-XRT Team Refined Analysis
  24. GRB 071104: Possible Swift UVOT Afterglow Candidate
  25. GRB 071104: Swift-XRT position
  26. GRB 071104: Gamma Ray Burst Localization by SuperAGILE
  27. GRB071010b: optical observation
  28. Swift XRT and UVOT observations of GRB071028B
  29. GRB 071101, Swift-BAT refined analysis
  30. GRB 071101: Swift-XRT Team refined analysis
  31. GRB071101: Optical and NIR upper limits by KANATA
  32. GRB0711101: Two new source from Xinglong TNT observation
  33. GRB 071101: TAROT Calern observatory optical observations
  34. GRB 071101: Swift XRT position
  35. GRB071101 LOAO B,V,R,I observation
  36. GRB 071101: BOOTES-2 prompt optical observations
  37. GRB 071101: a nearby galaxy
  38. GRB 071101: Swift detection of a burst
  39. GRB 071031, Swift-BAT refined analysis
  40. GRB 071031: Swift/UVOT detection of afterglow
  41. GRB 071031: Swift-XRT Team refined analysis
  42. GRB 071020: MITSuME Akeno optical observations
  43. GRB 071031: REM NIR and Optical observation
  44. GRB 071031, SMARTS afterglow observations
  45. GRB 071031: VLT high-resolution spectroscopy
  46. GRB071031: Rapid PROMPT Detections
  47. GRB 071031: GROND detection in all bands
  48. GRB 071031: Swift detection of a burst with an optical counterpart
  49. GRB 071028B Swift-BAT detection of a burst
  50. GRB071025: Optical+NIR observations
  51. GRB 071028: SARA observations of variable source
  52. Swift UVOT upper limits to GRB071028
  53. GRB071028: Xinglong EST V-band upper limit
  54. GRB 071028: Swift-XRT Team refined analysis
  55. GRB 071028, Swift-BAT refined analysis
  56. GRB 071028: Swift detection of a burst
  57. GRB 071025: Kuiper Telescope Optical Observations
  58. GRB 071003: Infrared Photometry with Keck Adaptive Optics
  59. GRB 071018: Revised BAT position
  60. GRB 071025A: RAPTOR Observations of Complex Early Optical Behavior
  61. GRB071021: MARGE Optical Limits
  62. GRB071020, optical upper limit
  63. GRB 071025: SARA VRI upper limits
  64. GRB 071025 Milagro GeV/TeV Observations
  65. GRB 071025: SQIID JHK photometry
  66. GRB 071025A: Complex Early-Time IR Behavior, Simultaneous with Gamma- and X-rays
  67. GRB071025: Optical Pre-imaging from Palomar
  68. Swift UVOT upper limits
  69. GRB071025: Xinglong TNT I-band upper limit
  70. GRB 071025: Swift-XRT Team refined analysis
  71. GRB 060602A: host redshift
  72. GRB 071025, Swift-BAT refined analysis
  73. GRB 071025: Early Super-LOTIS Observations
  74. GRB 071025: R/I-band update
  75. GRB071021 : CFHT Ks-band observation
  76. GRB 071025: ROTSE-III Refined Analysis
  77. GRB 071025: I-detection, R-dropout?
  78. GRB 071025: Swift XRT refined position
  79. GRB 071025a: PAIRITEL observations
  80. GRB071025: REM NIR afterglow
  81. GRB 071025: ROTSE-III Detection of Optical Counterpart
  82. GRB 071025: Swift detection of a burst
  83. GRB 071021: R-band detection and analysis
  84. GRB 071020: BTA spectroscopy
  85. GRB071021: Optical+NIR observations
  86. Possible radio detection of GRB 071021 with the VLA
  87. Optical observations of GRB 071020
  88. GRB 071021: (Relatively shallow) IR non-detections; motivation for optical spectroscopy
  89. GRB 071020: SARA observations
  90. Radio detection of GRB 071020 with the VLA
  91. GRB071010b: optical observation
  92. GRB 071021: Subaru NIR observation
  93. GRB071021: MITSuME Okayama Optical Upper Limits
  94. GRB 071021: Magellan i-band observation
  95. GRB 071021: Magellan R-band observation
  96. GRB 071021: Z-band detection
  97. GRB 071021: correction to GCNC 6968
  98. GRB 071020: Fading slowly?
  99. GRB 071010B: Fading quickly
  100. GRB 071021: optical and NIR observations

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