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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 071028: Swift-XRT Team refined analysis
  2. GRB 071028, Swift-BAT refined analysis
  3. GRB 071028: Swift detection of a burst
  4. GRB 071025: Kuiper Telescope Optical Observations
  5. GRB 071003: Infrared Photometry with Keck Adaptive Optics
  6. GRB 071018: Revised BAT position
  7. GRB 071025A: RAPTOR Observations of Complex Early Optical Behavior
  8. GRB071021: MARGE Optical Limits
  9. GRB071020, optical upper limit
  10. GRB 071025: SARA VRI upper limits
  11. GRB 071025 Milagro GeV/TeV Observations
  12. GRB 071025: SQIID JHK photometry
  13. GRB 071025A: Complex Early-Time IR Behavior, Simultaneous with Gamma- and X-rays
  14. GRB071025: Optical Pre-imaging from Palomar
  15. Swift UVOT upper limits
  16. GRB071025: Xinglong TNT I-band upper limit
  17. GRB 071025: Swift-XRT Team refined analysis
  18. GRB 060602A: host redshift
  19. GRB 071025, Swift-BAT refined analysis
  20. GRB 071025: Early Super-LOTIS Observations
  21. GRB 071025: R/I-band update
  22. GRB071021 : CFHT Ks-band observation
  23. GRB 071025: ROTSE-III Refined Analysis
  24. GRB 071025: I-detection, R-dropout?
  25. GRB 071025: Swift XRT refined position
  26. GRB 071025a: PAIRITEL observations
  27. GRB071025: REM NIR afterglow
  28. GRB 071025: ROTSE-III Detection of Optical Counterpart
  29. GRB 071025: Swift detection of a burst
  30. GRB 071021: R-band detection and analysis
  31. GRB 071020: BTA spectroscopy
  32. GRB071021: Optical+NIR observations
  33. Possible radio detection of GRB 071021 with the VLA
  34. Optical observations of GRB 071020
  35. GRB 071021: (Relatively shallow) IR non-detections; motivation for optical spectroscopy
  36. GRB 071020: SARA observations
  37. Radio detection of GRB 071020 with the VLA
  38. GRB071010b: optical observation
  39. GRB 071021: Subaru NIR observation
  40. GRB071021: MITSuME Okayama Optical Upper Limits
  41. GRB 071021: Magellan i-band observation
  42. GRB 071021: Magellan R-band observation
  43. GRB 071021: Z-band detection
  44. GRB 071021: correction to GCNC 6968
  45. GRB 071020: Fading slowly?
  46. GRB 071010B: Fading quickly
  47. GRB 071021: optical and NIR observations
  48. GRB 071021: possible high-z burst
  49. GRB 071021, Swift-BAT refined analysis
  50. GRB071018: 2nd epoch obsevations of Xinglong TNT
  51. GRB 071021: retraction of Faulkes Telescope South candidate
  52. GRB 071021: Swift-XRT Team refined analysis
  53. GRB 071021: Xinglong TNT optical Upper Limit
  54. GRB 071021 : Lulin R-band limit
  55. Konus-Wind observation of GRB 071020
  56. GRB 071021: Faulkes Telescope South optical candidate
  57. GRB 071021: Swift detection of a burst
  58. GRB 071010B: Independent Confirmation of Break
  59. GRB071020A: Xinglong TNT Optical afterglow observations
  60. GRB 071020: Swift-XRT refined analysis
  61. GRB 071020, Swift-BAT refined analysis
  62. GRB 071020A: IR Imaging with PAIRITEL
  63. GRB 071020: VLT spectroscopy
  64. GRB 071020: ROTSE-III Analysis of Optical Counterpart
  65. GRB071020 - SDSS Pre-burst Observations
  66. GRB 071020: Swift detection of a bright burst
  67. GRB 071020A: ROTSE-III Detection of Optical Counterpart
  68. GRB 071018: Mercator Telescope optical observations
  69. Swift autonomous slewing re-enabled
  70. GRB071010b: optical observations
  71. GRB 071018: SARA observations
  72. GRB 071018: Swift-XRT observation
  73. GRB 071017 - Swift XRT observations
  74. VLA radio observation of GRB 071018
  75. GRB071018: Correction to the GCN 6936
  76. GRB071018: Correction to the GCN 6936
  77. GRB071018: Correction to the GCN 6936
  78. GRB071018: Correction to the title of the GCN 6936
  79. GRB 071018: Possible OT from Xinglong TNT observation
  80. GRB 071010B: Light Curve Break Confirmed
  81. GRB 071010A: Late-time Keck/LRIS photometry - possible host galaxy and jet break
  82. GRB 071018, Swift-BAT refined analysis
  83. GRB 071018?: Swift detection of a possible burst
  84. GRB 071010B: Suzaku WAM observation of the prompt emission
  85. GRB 071013: 3rd TLS Epoch - constraints on variability
  86. GRB 071013: TNT optical data refined analysis
  87. GRB 071010B: Keck/DEIMOS emission-line redshift
  88. GRB 071017: a SHORT GRB detected by INTEGRAL
  89. GRB 071013: TLS 2nd epoch - Kornienko candidate constant
  90. GRB071013: optical observations
  91. GRB 071010B: Optical observations of EST
  92. GRB 071010B: TLS 3rd Epoch - finally a break??
  93. GRB 071011: MITSuME Optical Observations
  94. GRB 070920A: deep optical observations at the NOT
  95. GRB 071010B: Photometry after 1.6 days
  96. GRB 071010B: Keck/LRIS Photometry
  97. GRB 071010B: TLS 2nd Epoch, refined analysis
  98. GRB 071013: TLS Upper Limit
  99. Correction to GCN circular no. # 6915 for GRB 071010B
  100. VLA detection of radio afterglow of GRB 071010B

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