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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 071031: VLT high-resolution spectroscopy
  2. GRB071031: Rapid PROMPT Detections
  3. GRB 071031: GROND detection in all bands
  4. GRB 071031: Swift detection of a burst with an optical counterpart
  5. GRB 071028B Swift-BAT detection of a burst
  6. GRB071025: Optical+NIR observations
  7. GRB 071028: SARA observations of variable source
  8. Swift UVOT upper limits to GRB071028
  9. GRB071028: Xinglong EST V-band upper limit
  10. GRB 071028: Swift-XRT Team refined analysis
  11. GRB 071028, Swift-BAT refined analysis
  12. GRB 071028: Swift detection of a burst
  13. GRB 071025: Kuiper Telescope Optical Observations
  14. GRB 071003: Infrared Photometry with Keck Adaptive Optics
  15. GRB 071018: Revised BAT position
  16. GRB 071025A: RAPTOR Observations of Complex Early Optical Behavior
  17. GRB071021: MARGE Optical Limits
  18. GRB071020, optical upper limit
  19. GRB 071025: SARA VRI upper limits
  20. GRB 071025 Milagro GeV/TeV Observations
  21. GRB 071025: SQIID JHK photometry
  22. GRB 071025A: Complex Early-Time IR Behavior, Simultaneous with Gamma- and X-rays
  23. GRB071025: Optical Pre-imaging from Palomar
  24. Swift UVOT upper limits
  25. GRB071025: Xinglong TNT I-band upper limit
  26. GRB 071025: Swift-XRT Team refined analysis
  27. GRB 060602A: host redshift
  28. GRB 071025, Swift-BAT refined analysis
  29. GRB 071025: Early Super-LOTIS Observations
  30. GRB 071025: R/I-band update
  31. GRB071021 : CFHT Ks-band observation
  32. GRB 071025: ROTSE-III Refined Analysis
  33. GRB 071025: I-detection, R-dropout?
  34. GRB 071025: Swift XRT refined position
  35. GRB 071025a: PAIRITEL observations
  36. GRB071025: REM NIR afterglow
  37. GRB 071025: ROTSE-III Detection of Optical Counterpart
  38. GRB 071025: Swift detection of a burst
  39. GRB 071021: R-band detection and analysis
  40. GRB 071020: BTA spectroscopy
  41. GRB071021: Optical+NIR observations
  42. Possible radio detection of GRB 071021 with the VLA
  43. Optical observations of GRB 071020
  44. GRB 071021: (Relatively shallow) IR non-detections; motivation for optical spectroscopy
  45. GRB 071020: SARA observations
  46. Radio detection of GRB 071020 with the VLA
  47. GRB071010b: optical observation
  48. GRB 071021: Subaru NIR observation
  49. GRB071021: MITSuME Okayama Optical Upper Limits
  50. GRB 071021: Magellan i-band observation
  51. GRB 071021: Magellan R-band observation
  52. GRB 071021: Z-band detection
  53. GRB 071021: correction to GCNC 6968
  54. GRB 071020: Fading slowly?
  55. GRB 071010B: Fading quickly
  56. GRB 071021: optical and NIR observations
  57. GRB 071021: possible high-z burst
  58. GRB 071021, Swift-BAT refined analysis
  59. GRB071018: 2nd epoch obsevations of Xinglong TNT
  60. GRB 071021: retraction of Faulkes Telescope South candidate
  61. GRB 071021: Swift-XRT Team refined analysis
  62. GRB 071021: Xinglong TNT optical Upper Limit
  63. GRB 071021 : Lulin R-band limit
  64. Konus-Wind observation of GRB 071020
  65. GRB 071021: Faulkes Telescope South optical candidate
  66. GRB 071021: Swift detection of a burst
  67. GRB 071010B: Independent Confirmation of Break
  68. GRB071020A: Xinglong TNT Optical afterglow observations
  69. GRB 071020: Swift-XRT refined analysis
  70. GRB 071020, Swift-BAT refined analysis
  71. GRB 071020A: IR Imaging with PAIRITEL
  72. GRB 071020: VLT spectroscopy
  73. GRB 071020: ROTSE-III Analysis of Optical Counterpart
  74. GRB071020 - SDSS Pre-burst Observations
  75. GRB 071020: Swift detection of a bright burst
  76. GRB 071020A: ROTSE-III Detection of Optical Counterpart
  77. GRB 071018: Mercator Telescope optical observations
  78. Swift autonomous slewing re-enabled
  79. GRB071010b: optical observations
  80. GRB 071018: SARA observations
  81. GRB 071018: Swift-XRT observation
  82. GRB 071017 - Swift XRT observations
  83. VLA radio observation of GRB 071018
  84. GRB071018: Correction to the GCN 6936
  85. GRB071018: Correction to the GCN 6936
  86. GRB071018: Correction to the GCN 6936
  87. GRB071018: Correction to the title of the GCN 6936
  88. GRB 071018: Possible OT from Xinglong TNT observation
  89. GRB 071010B: Light Curve Break Confirmed
  90. GRB 071010A: Late-time Keck/LRIS photometry - possible host galaxy and jet break
  91. GRB 071018, Swift-BAT refined analysis
  92. GRB 071018?: Swift detection of a possible burst
  93. GRB 071010B: Suzaku WAM observation of the prompt emission
  94. GRB 071013: 3rd TLS Epoch - constraints on variability
  95. GRB 071013: TNT optical data refined analysis
  96. GRB 071010B: Keck/DEIMOS emission-line redshift
  97. GRB 071017: a SHORT GRB detected by INTEGRAL
  98. GRB 071013: TLS 2nd epoch - Kornienko candidate constant
  99. GRB071013: optical observations
  100. GRB 071010B: Optical observations of EST

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